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1Back to top Go down   Testing Temperature Switching Relay Empty Testing Temperature Switching Relay on Wed Mar 10, 2010 11:09 am

Loner0831

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Here's a simple one for our experts here. My bike is a 1987 K100 RT that's been stored for several years due to some undiagnosed malfunction by a previous owner. I have traced the problems to at least two areas. First it has a faulty fuel pump, and I will purchase an appropriate substitute as discussed in other areas of this forum. For the second suspect problem, however, I need a touch of advice. I am reasonably sure the Temperature Relay is faulty. Pin #45 has 12v+ with the switch on. If I jump 12v+ to Pin #A2 the fan operates. If I jump a ground (12v-) to Pin #A3 I get the indicator light as it should. If I ground Pin #E, I get nothing (should power fan and indicator light as I understand it). That last test indicates a faulty relay, right?

Also, if the Temperature Relay works properly, when it has 12v+ applied to Pin #45, and it is properly grounded through the ground pin, should I see 12v+ going out Pin #9 to the FI relay (which would also send powere to the fuel pump)? I have the diagrams available on this tech forum, but can't quite make out the complete power flow in this relay.

Thanks in advance for your help! Testing Temperature Switching Relay Icon_smile

    

2Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 10, 2010 4:26 pm

Crazy Frog

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@Loner0831 wrote:Here's a simple one for our experts here. My bike is a 1987 K100 RT that's been stored for several years due to some undiagnosed malfunction by a previous owner. I have traced the problems to at least two areas. First it has a faulty fuel pump, and I will purchase an appropriate substitute as discussed in other areas of this forum. For the second suspect problem, however, I need a touch of advice. I am reasonably sure the Temperature Relay is faulty. Pin #45 has 12v+ with the switch on. If I jump 12v+ to Pin #A2 the fan operates.
Right you are bypassing the internal relay

If I jump a ground (12v-) to Pin #A3 I get the indicator light as it should.
Right again, this is like having a high water temperature

If I ground Pin #E, I get nothing (should power fan and indicator light as I understand it). That last test indicates a faulty relay, right?
Right again. This is telling the temperature switching unit that the water temperature is very high and there is no resistance between the ground and the temperature gauge

Also, if the Temperature Relay works properly, when it has 12v+ applied to Pin #45, and it is properly grounded through the ground pin, should I see 12v+ going out Pin #9 to the FI relay (which would also send power to the fuel pump)? I have the diagrams available on this tech forum, but can't quite make out the complete power flow in this relay.
I don't think so. When the fuel injection relay is energized, it send 12v + to the temp unit. The temp unit receives the power from the FI relay and don't send it to the FI relay.
I just noticed that I mis-labeled the pin # of the temp unit on the interactive diagrams. Pin #E should be # 15 (or 45 on some other diagrams) and pin #15 should be #E. When I made these diagrams, I was following a scanned schematic and it was difficult to read the pin #. Pin #15 could be read as 45. Sorry about this. I will correct it.


Bert (I am not not an expert Embarassed, but I have spent a lot of time studying the electric of the K100 )


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3Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 10, 2010 6:37 pm

Loner0831

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OK, Bert. I'm almost understanding. But looking at your diagram below which is depicted in the actual pin layout design of the relay, two questions:
1) Pin 9 is truly the incoming connection from the FI relay, right?
2) If the Temp Relay has 12v+ coming in from the Load Shed Relay, what is the function of 12v+ sent in from the FI relay?

Be patient with me, but depending on your answer I may have a Temp Relay problem, or I may have to move on to test the FI relay.

Testing Temperature Switching Relay Fan%20circuit

    

4Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 10, 2010 9:18 pm

Crazy Frog

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First, I never open a temperature switching unit and I don't have the internal schematic.
I assume that pin 45 is the power for the fan and pin #9 is the power for the electronic circuit.
This is my own interpretation as I don't have any data to backup this. I am not an electrician (but a jack of all trades) and I would like to know what the professionals are thinking of this idea.

On one of the recent post about the fan, Ned said: "The fan sucks a lot of current, so weak battery may only spin it and not at the intended speed which I measure to be 4220 rpm. I think that the spec is 4200 rpm."

This is why I am thinking that the control circuit may be different than the power circuit. The schematic of the temp unit represents a built in relay and why would you have the coil on the same circuit as the power leads? The purpose of a relay is to use a low power device (coil) to control a high power switching unit. In reality, what is represented as a relay could be a thyristor. in electronic circuits a thyristor acts as a relay too.

Bert


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Testing Temperature Switching Relay Frog15Testing Temperature Switching Relay Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

5Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Mar 11, 2010 2:56 am

Loner0831

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I think we're agreed on the temp relay operation, Bert. The 12v+ in from the FI relay powers the coil when activated by a 12v- (ground, or approaching ground by the varied resistance level) signal from the temp sensor (signaling an overheat situation).

When the temp relay coil is then activated, the higher amperage 12v+ in on #45 is circuited to the fan, and at the same time #A3 is grounded to turn on the gauge light (in essence a double-pole relay).

This sounds proper to me, and I didn't want to open up the temp relay cover unless I just had to. I'll test with this circuitry later this morning to verify (it's 12:45AM here right now - middle of the night). Since I've not tested it's operation with this circuitry in mind, I may indeed have a good temp relay and if so will have to move on to the FI relay for testing and perhaps the FI module beyond that.

Honestly, I bought the bike with this problem to purposely challenge myself in keeping my logic nad schematic skills honed.

Thanks for the help and I send my regards to another night owl (I see your post was 1:18AM).

Larry (Loner0831)

    

6Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Mar 11, 2010 6:42 am

Ned

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@Crazy Frog wrote:First, I never open a temperature switching unit and I don't have the internal schematic.
I assume that pin 45 is the power for the fan ....

On one of the recent post about the fan, Ned said: "The fan sucks a lot of current, so weak battery may only spin it and not at the intended speed which I measure to be 4220 rpm. I think that the spec is 4200 rpm."

This is why I am thinking that the control circuit ....

Bert

Hi all,

Been away for a few days.

Can I comment on pin 45... I think that it may be 15. I remember reading somewhere that all you need to do is connect 15 to A2 and the fan should come on. see this:
Testing Temperature Switching Relay Fuseboxlayoutguide

My comment on current fan consumes is that my fan runs very slowly. I have a spare which I was servicing and testing using an old, small battery. After a few tests, the fan stopped and started to oscillate. After a short panic it become was obvious that the battery didn't have the capacity.

My next job is to remove the old fan and put the spare in. Can you do it without disconnecting the radiator hoses ?

    

7Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Mar 11, 2010 7:12 am

Crazy Frog

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@Ned wrote:
I remember reading somewhere that all you need to do is connect 15 to A2 and the fan should come on.
Yes this right. You may have been reading this earlier on this topic Laughing

I think the radiator has to be removed to replace the fan.


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8Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 31, 2010 10:23 am

rx35285

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Larry - are you done with the temp switch? If not, I'd like to pass along that I am able to run my '92 K75S with the temp switch removed. I know it is integrated with other components and I don't think I damaged anything, but I might have.

My fan runs all the time and I've had my switch open several times in the course of trying to figure out whether the problem is the temp probe, the fan switch, or something else. I learned nothing from opening it, except that the relay was just fine and there are 24 other components in there.

I couldn't tell from the replies whether you had your pin E question answered. Pin E is the lead from the temp sensor. You can read the sensor resistance between E and 31. As mentioned above, the cct power comes from 9.

Hope this helps -
Dave in Cedar Falls, IA
brand new member thanks to Bert's encouragement

    

9Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 31, 2010 6:52 pm

Ned

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@Crazy Frog wrote:
@Ned wrote:
I remember reading somewhere that all you need to do is connect 15 to A2 and the fan should come on.
Yes this right. You may have been reading this earlier on this topic Testing Temperature Switching Relay Icon_lol

I think the radiator has to be removed to replace the fan.


Correct, unfortunately. There was a glimmer of hope that I could simply tilt the fan forward, undo the bottom countersink screws and pull the fan out, but one of the screws was hidden behind the temp sensor, so the radiator had to come out. Just as well. The rubber grommet that holds the top mount in place is bitch to push through teh fan mount hole.



Thank goodness for flex shaft screwdrivers that can take hex and crew bits, else I would be accused of contaminating young minds with language that is not fit for mixed company. Removing bits of fairing and rubber air deflectors took a lot of time.



Now I need to refill the radiator and hope that the houses are holding pressure without leaks. The truth is that I didn’t really want to crack a perfectly good cooling system just to replace the fan.



I am installing a manual switch so that I can switch the fan on from time to time to make sure it works.

    

10Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 31, 2010 6:55 pm

Crazy Frog

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rx35285,

I am sure that you will be happy to belong to this group of knowledgeable people ready to share their expertise with others. Your first post was not asking for assistance, but sharing your experience. Very nice intro!
we are fortunate to have a lot of people like you on the forum.

Dave didn't know the forum but Emailed me about the interactive electrical diagrams and pointed a mistake. It's always a nice feeling when a perfect stranger drops you an Email and first say thank you for the work that you did for the community and at the same time point the correction that has to be made.

Warm welcome to the forum.

Bert


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11Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Mar 31, 2010 10:57 pm

rx35285

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Ned, I plan to install a manual switch, too, but haven't thought about in which circuit I'll put it, ie power cct to fan or control signal to fan switch. What are you planning to do?

Thanks,
Dave

    

12Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 01, 2010 10:40 pm

Ned

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Good point. I haven't looked at the circuits yet, but I think that I will look at using a fused line directly from the +12v or +12v on the other side of the ignition circuit. I only want to be able to switch the fan on for testing purposes. I think that the temp sensor is reliable enough to do the job automatically.

What I may do today is use my point-and-shoot thermometer to see at what temp the fan does come on.

    

13Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 01, 2010 11:10 pm

rx35285

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That sounds like something I could handle. The reason for asking is that I wonder how robust a switch would need to be if it is put in the fan power feed.

I predict the fan will come at 103C.....per the information on the IBMWR.org site. Would be interesting to see what you get.

Cheers.
Dave

    

14Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 01, 2010 11:37 pm

K-BIKE

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Hi Dave,
The fan should not draw any more than 5 amps running but the stalled current is around 10 amps possibly more so if you used a 10 amp switch you should be fine bearing in mind the number of times you are likely to switch it on and off are going to be relatively small compared to say the ignition switch.
Regards,
K-BIKE

    

15Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 02, 2010 5:17 am

blaKey

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My previous owner tapped into the yellow/purple wire just behind the fan and got power from a "always hot" point up behind the instruments by the look of things. Then he stuck in a rocker (non-illuminated) switch next to the 4-way flasher switch.

When I need the fan or even just to run it, I just push the switch and away it goes.
He also had the smarts to put in an in-line fuse as well.


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Dress for the ride and the potential slide.
    

16Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 02, 2010 6:40 am

Ned

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@blakey wrote:My previous owner tapped into the yellow/purple wire just behind the fan and got power from a "always hot" point up behind the instruments by the look of things. Then he stuck in a rocker (non-illuminated) switch next to the 4-way flasher switch.

When I need the fan or even just to run it, I just push the switch and away it goes.
He also had the smarts to put in an in-line fuse as well.

Yes that is a simplest way to do it and I will probably try it, but first I wonder if I can energize the fan relay (I assume that it is a relay) by simply tapping into the temp sensing unit and shorting pin 15 and A2 or was it 9 and A2? The reason I like to do this is that fuses are already there and we are using the existing circuits. Any ideas or objections?

    

17Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Tue Apr 06, 2010 11:34 pm

rx35285

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@Ned wrote:
@blakey wrote:My previous owner tapped into the yellow/purple wire just behind the fan and got power from a "always hot" point up behind the instruments by the look of things. Then he stuck in a rocker (non-illuminated) switch next to the 4-way flasher switch.

When I need the fan or even just to run it, I just push the switch and away it goes.
He also had the smarts to put in an in-line fuse as well.

Yes that is a simplest way to do it and I will probably try it, but first I wonder if I can energize the fan relay (I assume that it is a relay) by simply tapping into the temp sensing unit and shorting pin 15 and A2 or was it 9 and A2? The reason I like to do this is that fuses are already there and we are using the existing circuits. Any ideas or objections?

K-Bike, thanks for the explanation and clarification regarding the cooling fan loads.

I think I'm going to do it blakey's way (those dash panel switches aren't cheap!), but I think you can energize the fan relay by taking E to ground which would make the switch think the temp sensor resistance had gone to zero. Power from 9 would travel through the relay coil to E and ground. I've read elsewhere that the fan is supposed to come on when the temp sensor resistance gets down to 500-550 ohms (I don't recall for sure). BUT, are there any components inside the switch that would be damaged if they saw higher current due to zero resistance instead of the 500-550 ohm resistance?

BTW, I did find out my fan switch was bad - there's a short in it that energizes the relay when the engine starts. If I get really bored I might start removing components and testing them.

Dave in Iowa

    

18Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 12:53 am

Ned

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@rx35285 wrote:
@Ned wrote:
@blakey wrote:My previous owner tapped into the yellow/purple wire just behind the fan and got power from a "always hot" point up behind the instruments by the look of things. Then he stuck in a rocker (non-illuminated) switch next to the 4-way flasher switch.

When I need the fan or even just to run it, I just push the switch and away it goes.
He also had the smarts to put in an in-line fuse as well.

Yes that is a simplest way to do it and I will probably try it, but ....

K-Bike, thanks for the explanation and clarification regarding the cooling fan loads.

I think I'm going to do it blakey's way (those dash panel switches aren't cheap!), but I think you can energize the fan relay by taking E to ground ...
BTW, I did find out my fan switch was bad - there's a short in it that energizes the relay when the engine starts. If I get really bored I might start removing components and testing them.

Dave in Iowa

I did a search for this and found that Bert suggested the E to Ground thing some time ago. Not sure what will happen if you did that, but I suspect that someone has already tried it. Let's ask ...

My proposal is to install a switch between Pin31 and E.

    

19Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 4:13 am

Crazy Frog

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You have two solutions:

1st solution is to ground pin E with a rocker switch and this would be my preferred solution as next to no power is passing through the switch.

2nd solution is to short pin 45 and A2 but the switch will have to be strong enough to withstand the power required by the fan.


Testing Temperature Switching Relay Fan_ci10

Remember, the resistance of the temperature sensor decreases as the water temperature rises. At 103 degrees (temperature when the fan should start) the resistance is minimal.

Testing Temperature Switching Relay Water%20temperature


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20Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 10:19 am

rx35285

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Ned and Bert, thanks for the confirmation. I am disappointed in that I couldn't find Bert's information before I took up space with my post.

Bert, RE: your diagram above, the excellent work has me shaking my head in wonder.

This is a little off topic, but is the fan supposed to sound like a small airplane when it's running? I thought I would ask before I pull it and try to lubricate it or replace the motor. It does move a lot of air, and it moves easily when I push it by hand, but I wouldn't say it free wheels.

Thanks, Dave in Iowa

    

21Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 4:41 pm

Crazy Frog

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If you get the time, remove it to clean it. My fan doesn't turn freely, but I can turn it with one finger feeling a small resistance
Few words of advise for everybody:
Never, never use a pressure washer directed to the radiator. This is the best way to burn your fan.
If you do it, the water will sit on the brushes creating electrical arcs. This will generate heat and melt the brush holders.


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22Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 6:36 pm

blaKey

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Dave (rx35285), my fan roars when it's switched on and I can feel the "breeze" mainly from the right side of the bike through the three vents on the fairing.
The rocker switch used to turn it on is a cheap one and not a genuine BMW switch. But I'm thinking of getting a BMW switch just to make it look a bit more "factory fitted".


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Dress for the ride and the potential slide.
    

23Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 7:37 pm

Ned

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[quote="rx35285"]
Ned and Bert, thanks for the confirmation. ...

No problems Smile

Bert, RE: your diagram above, the excellent work has me shaking my head in wonder.
I second that, great work

This is a little off topic, but is the fan supposed to sound like a small airplane when it's running? ....
Yes, it runs at 4500 rpm and although it is a small fan (approx 7 inch) it has large blades and is rate at 28W. If it runs any slower then you will have a problem, like I did, and will need to be removed and checked.

If it makes squealing noises on start up and just before it stops, the bearings are dry and probably worn. If that is the case I would replace the motor because the motor assembly is crimped and would be hard to take apart and reassembled.

The problem with the fan is the front sleeve bearing... there is no way to get to it until you remove the fan and take the fan blades off.

Anyway the motor is reasonably cheap (approx $100 or so) is available from Bosch and others, so you can easily rebuild the thing.

    

24Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 7:52 pm

Ned

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@Crazy Frog wrote:You have two solutions:

1st solution is to ground pin E with a rocker switch and this would be my preferred solution as next to no power is passing through the switch.

2nd solution is to short pin 45 and A2 but the switch will have to be strong enough to withstand the power required by the fan.
....

Hi Bert,
Your second solution is fine but I prefer the first, as you say less current involved. However, I like to clear up something...
The sensor supplies a signal (volts varying by changing resistance?) to the FI "computer" and also a signal to the switch (pin E). Is this correct?
If so and if we ground this at any point there will be no resistance in the circuit. Is there a chance that we are going to provide a short and zap either the switch, sensor or the FI unit?

I only ask this because I am likely to try it this weekend. Our weather has dropped below 30C and the use of the fan is not likely in my case, so I would like to run it manually to make sure all is ok.

    

25Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Wed Apr 07, 2010 10:25 pm

Crazy Frog

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Ned,

Good thinking!

From the electrical schematic, you can see that the temperature unit sensor contains 2 sensors:
One is feeding information to the FI computer and the other is feeding information to the temperature unit. Why BMW designed a double sensor is a mystery to me but this maybe just a security to avoid blowing up the computer if the temperature unit has a problem.
You only have 50% of chances to pickup the wrong wire as both have the same colors Smile
You can use an Ohmmeter to find exactly which wire is going to the temperature unit. Grounding one of them will tell the system that the engine is overheated. If you pickup the wrong wire (the one going to the EFI), the engine should not start. If you pickup the right one, the temperature light should glow.

As I always emphasis, I am not a professional and what I express is my personal opinion and experience. I am reading the schematics and try to understand how the Teutonic engineers designed the system (I think they did a good job). When somebody wants to make a modification to the original design, he always have a slight chance of being wrong. In this case, I am 99.999% certain that this solution is correct but I haven't tried it. Keeping the original circuit with the option to bypass it is what I believe is the best.

Bert


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26Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 08, 2010 6:56 am

Ned

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Hi,

It's just me again. I've poked around my files and found some more info re: temp relay circuits. This is it:

Testing Temperature Switching Relay K100_Early_Wiring_Diagram-temp%20sensor

The excerpt from a K100 diagram.

The sensor is input through prong E is a base of a NPN transistor which acts as a switch, if we are to believe the diagram. I am nor sure what the 54a and 58a labels are except that they may be a model of the transistor.

Prong 9 provides 12V which passes on to A2 through an internal relay switched on by the transistor.

OK, my question is : knowing this can we simply connect the base to ground ?
Sorry Bert, but my knowledge of these circuits is lacking... any ideas?

    

27Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 08, 2010 3:58 pm

ReneZ

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Easiest is to remove the temp relais from the relais box and look at the wires underneath. Then connect a wire to the wire at "E" and connect that one with a switch to earth. That's what I have done and it works like a charm. If you connect it to earth also the red light in the display will come on, normally signalling too high temperature, but now also that your fan is on. It does mean that the alarm function is no longer working when you have manually connected the fan.
BTW 54A and 58A are EU wiring code indentifiers.


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Greetings from Florida! Having a 'new' K  :cyclops:    Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Testing Temperature Switching Relay Rain
BMW K1200GT - 2003 (ZK01223)
    

28Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 08, 2010 5:53 pm

Crazy Frog

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Thanks for the confirmation of my theory.
The good thing is that by fooling the temp unit, the red light let you know that the manual fan switch is turned ON.

At least we have somebody that did it.

Ned what are you doing this week end ? Wink


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29Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 08, 2010 7:47 pm

Ned

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Thank you Bert and ReneZ. Yes I have a switch and one 12V high intensity LED. I was going to do exactly what ReneZ suggested with the exception that I will connect the prong 31 (earth) to prong E via the switch.

that should take a few hours or few beers whichever comes first, then I will install my new fuel regulator and when I am at it the new thermostat (OEM kind).

Sunday... all going well, me and a mate will be doing the pub ride ... from my place to Wollongong via Scarborough Pub, to the Robertson Pub up a twisty pass, then to Albion, through the Kangaroo valley (down hill twisty bits) and then back through the Royal National park.

That should be at least 3-4 pubs and a tank of fuel. A good test me thinks. Smile

Again, thanks for the solution and the conformation.

    

30Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Apr 08, 2010 9:33 pm

Crazy Frog

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@Ned wrote:that should take a few hours or few beers whichever comes first

Hey we are talking the same language.... Beer comes first (or scotch), but never when I am riding.
This reminds me the type of warranty that I give to my users at work.... 30/30. 30 seconds or 30 feet. Whatever comes first.


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31Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Sat Apr 10, 2010 4:54 am

Ned

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Two beers later I managed to :

  1. change my thermostat. she now has the OEM 85c unit
  2. changed the pressure regulator. she now holds the pressure when I switch off. That gives me confidence that the rest of the EFI system is working well, i.e. no leaky injectors etc.
  3. Took the temp sensor out and had a look inside. Unfortunately, I didn't have time to do the electrical work and fit the fan switch. However, here are a few pics of the switch sensor internals:
Testing Temperature Switching Relay DSC00268

now I don't see anything that looks like a relay although there is a small transistor in the top RH corner (black blob). The two ICs are a NAND gate and a light balance comparator.. i suspect it is used to trigger the fan, but I see nothing heavy enough to switch approx 4A.

BTW my fan kicked in at 88c, measured by IR thermometer. that is lower than expected but it is fine. This was done at idle... let's see what happens on the highway.

    

32Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Sat Apr 10, 2010 10:48 am

rx35285

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The guts of the switch in my '92 K75S look quite different. I'll take a picture and post it in case there are others who have an older version like mine. I figure Ned's is newer since it doesn't have an electro-mechanical relay.

Cheers,
Dave

    

33Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Sat Apr 10, 2010 7:07 pm

K-BIKE

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Hi Ned,
I think the temperature sensor switches a fan relay which handles the current.
Regards,
K-BIKE

    

34Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Sun Apr 11, 2010 8:33 pm

Ned

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First of all, it all seems to work well ... yesterday I took the bike through suburban shopping centre traffic to see a mate (problems with his Yamaha). The temperature was in the high 20s so the fan turned on and off at regular intervals.

BTW the actual switch on temp is around 88c, according to IR thermometer.

Two things that struck me:
  • the fan is "new" and it comes on instantly as it should,

  • it goes off with a kind of a whimper and a hesitation, not at all like a relay click one expects


The relay? Not that it matters, but where is it, I can't see it on the drawings so I assumed that it was incorporated into the switch. Any ideas?

    

35Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Sun Apr 11, 2010 8:43 pm

Crazy Frog

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You are totally right that the fan doesn't shut off instantly. Don't ask me why because it's a mystery to me too. I think I could have an explanation with an electronic circuit (Transistors/thyristors), but can't explain why it works like this with a relay.
The relay is incorporated to the temperature unit.


__________________________________________________
Testing Temperature Switching Relay Frog15Testing Temperature Switching Relay Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

36Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 16, 2010 12:07 am

rx35285

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Here's a switch from a '92K75S. Which one of those little buggers on that board is causing the relay contacts to stay closed???? First guess is a diode since a resistance measurement between two of the terminals (don't recall which two at the moment) shows 10K ohms on a good switch and "open" on this switch. Dave. Testing Temperature Switching Relay CIMG3736

    

37Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 16, 2010 5:34 am

Ned

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yours looks different. You at least have a relay.

My knowledge of electronics is very limited and without a circuit diagram I am lost, however, the chip is a comparator. I think that it is the thing that decides when the fan is to switch on.

To me, the active components are the two transistors, electrolytic capacitor and the relay.

Now nothing looks burnt, so I would concentrate on things like the capacitor (known to fail) first. maybe the relay it self is playing up, it is mechanical after all.

    

38Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 16, 2010 1:32 pm

rx35285

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The relay is good - looks and works like brand new when I put 12 V across the coil. I am lost after that. Would a diode likely look burnt if it failed? If yes, then maybe I'll try to figure out if the capacitor is in the coil circuit and replace it if it is. This is way down the list since I have a good switch installed and it's the start of riding season.

Ned, glad you got your fuel issue sorted out. Nice work on the diagnosis.

Ride safe, Dave

    

39Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 16, 2010 2:50 pm

Avenger GT

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Diodes almost always go short circuit when faulty. When tested with a multimeter set to diode check (or 2k ohms if the meter does not have diode check) it will read very low resistance in both directions. Testing in circuit is not always conclusive because other components may be in parallel with the diode giving a false reading. Sometimes a diode can go leaky and test OK with a meter but break down in circuit. The only time a faulty diode would look burnt is if it got a mighty surge of current through it, or a much bigger voltage across it than it was designed to take which would short it out and give the mighty surge of current anyway. The external physical appearance of most electronic components almost always looks the same whether they are good or faulty, so the only way of checking them is with meter and oscilloscope, or substitution. Testing Temperature Switching Relay Icon_scratch

    

40Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 16, 2010 4:41 pm

rx35285

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@Avenger GT wrote:Diodes almost always go short circuit when faulty. When tested with a multimeter set to diode check (or 2k ohms if the meter does not have diode check) it will read very low resistance in both directions. Testing in circuit is not always conclusive because other components may be in parallel with the diode giving a false reading.....Testing Temperature Switching Relay Icon_scratch

Thanks for the diode explanation and the insights about components that don't release smoke on failure. Now I'm getting more curious and might have to raise the priority to a rainy day, rather than a cold weather, project. I can look back in my notes to see which terminals read open with the ohm meter connected one way and 10K with the leads switched, then maybe do a little circuit tracing (keeping in mind the high potential of a false reading due to parallel components) and make some informed guesses as to which component to remove first. Dave.

    

41Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Apr 16, 2010 6:15 pm

K-BIKE

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Hi All,
One problem which manifests with most vehicles of our vintage is bad solder joints and vibration induced cracking plus stress induced corrosion. When a component sticks up above the board there will be a natural vibration frequency where it will vibrate back and forth.

That is why on bridges large groups of soldiers marching are ordered to break step so they avoid synchronised shocks to the bridge. Stress cracking of solder joint takes place over time as the component waggles back and forth plus small amounts of damp which are around our bikes from time to time Very Happy get into these modules and help the failure of the joint.

Very careful examination of the solder side of the board with a jewellers magnifying glass will usually reveal cracking around one or more component wires where they poke through the board and project through the solder. Often there is a greyish look to the area. These are sometimes called cold joints because the same effect can happen if the solder was not kept hot long enough to heat the wire and the solder did not wet the wire surface to form an alloy and make the bond.

Getting a good soldering iron and proper electronic grade solder will enable you to re-flow each solder joint. Do that by working on one end of the component at a time and with semiconductors like diodes or transistors be careful not to cook the transistor by keeping the heat on too long. With those, do one joint and then work on another component only returning to the transistor after a couple of minutes to allow the device to cool. Then do the next lead and again wait, finally soldering the last.

With components that are very heat sensitive sometimes a heat shunt is clipped to the wire lead above the circuit board on the other side to absorb excess heat conducted up the wire and stop it reaching the semiconductor junction. I have rescued a number of car and bike circuit modules by re-soldering the components.
Regards,
K-BIKE

    

42Back to top Go down   Testing Temperature Switching Relay Empty Temperature switch / relay on Thu Jan 21, 2016 3:22 pm

Big G

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@Ned wrote:Two beers later I managed to :

  1. change my thermostat. she now has the OEM 85c unit
  2. changed the pressure regulator. she now holds the pressure when I switch off. That gives me confidence that the rest of the EFI system is working well, i.e. no leaky injectors etc.
  3. Took the temp sensor out and had a look inside. Unfortunately, I didn't have time to do the electrical work and fit the fan switch. However, here are a few pics of the switch sensor internals:

Testing Temperature Switching Relay DSC00268

now I don't see anything that looks like a relay although there is a small transistor in the top RH corner (black blob). The two ICs are a NAND gate and a light balance comparator.. i suspect it is used to trigger  the fan, but I see nothing heavy enough to switch approx 4A.

BTW my fan kicked in at 88c, measured by IR thermometer. that is lower than expected but it is fine. This was done at idle... let's see what happens on the highway.
Hi guys

Old post, but . . . .

Is this not a picture of the bulb monitor/lamp test unit?


__________________________________________________
1990 K100 RS (2015 - Current)
2005 R1150 GS - 35000 km (2007 - 2010)
1980 R80 GS - 28000 km (2005 - 2006)
2000 F650 GS - 102000 km (2000 - 2004)
1984 Suzuki Katana 750 - 72000 km (1984 - 1986)
1982 Suzuki DR500 - 48000 km (1982 - 1984)
    

43Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Thu Jan 21, 2016 5:23 pm

rx35285

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Good catch Big G!!

Here is a picture of the temperature control I replaced in 2010.  The relay is clearly apparent in the top of the pic near the middle.  The good news is that I think I found a cracked joint.  Good Karma must be in play.  A fine tip for my soldering gun was delivered yesterday and now this post by Big G.

Testing Temperature Switching Relay K75_co11

Now I need to apply K Bike's 2010 advice about solder cracks.

Dave in Iowa, US.

    

44Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Jan 22, 2016 1:12 am

Holister

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We'll have to cut Ned a bit of slack I think... he did say he'd had two beers drunken


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Testing Temperature Switching Relay Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

45Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Jan 22, 2016 10:07 am

rx35285

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Yeah, I should have mentioned that I had only ONE beer.  Didn't want to tease Ned too much.  I'll probably be relying on his expertise in the future.

    

46Back to top Go down   Testing Temperature Switching Relay Empty Re: Testing Temperature Switching Relay on Fri Jan 22, 2016 10:22 pm

Ned

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@rx35285 wrote:Yeah, I should have mentioned that I had only ONE beer.  Didn't want to tease Ned too much.  I'll probably be relying on his expertise in the future.
Thank you for picking it up. Clearly 2 beers is beyond my limits Smile  Embarassed

I don't remember how that controller thing finished but I had A RELIABLE fan after I was forced to swap it for another. The PO patched the old fan internals with epoxy and tape Smile It did look good from the out side.

BTW my old girl is up for sale so anone in Australia interested message me. I also have a k1200 to play with as well.

Ned


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Ned

05/1986 (K55) K100RS Motorsport (Europe), Production Code: 0503, 110k km, VIN:0140519 (SOLD)
1976 Honda Goldwing GL1000 (naked)
1997 BMW K1200RS red, VIN: WB10544A1VZA22667
    

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