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1Back to top Go down   temp switch and bulb monitoring units Empty temp switch and bulb monitoring units Thu Mar 18, 2021 12:30 pm

tinyspuds

tinyspuds
Life time member
Life time member
In my box of k100 I have a fuse box/relay tray that I was going to use for spares after testing. All going well until I took out the temp and bulb monitoring units. Obviously many more pins than I was expecting and a non-DIN numbering schema.
I know the temp switch at least has a coil in it that I can test and I’ve read enough of Bert’s stuff to (maybe) design a testing regime that makes these components worth carrying. But, before I do, has someone already done this? I may still be locked down, but even so I don’t want to reinvent the wheel. 

Also, does anyone know what the numbering schema used is called so that I can do more reading? Cheers, Stu


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

robmack

robmack
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This thread will give you schematics for many of the BMW OEM modules: https://www.k100-forum.com/t13127-reference-bmw-instrument-cluster-schematics  

Unfortunately, I haven't produced one for the temp sensing unit.

The temp sensing unit is much more than a relay; it contains a sophisticated electronic circuit that monitors water temps and controls the fan accordingly.  I posted the terminal designations in this thread:  https://www.k100-forum.com/t16871-93-k75-temp-sensor-relay-wiring#194593


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

tinyspuds

tinyspuds
Life time member
Life time member
You’re a gent Rob, thanks.


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

robmack

robmack
Life time member
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See this link for instructions on how to test the temperature sensing module: https://ibmwr.org/index.php/2000/06/01/gas-mileage-problems/


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
How about doing a function check by plugging them into the relay box of a running bike and see what they do?

Run the engine temperature up while idling and see if the fan comes on.

Check the bulb monitor by running the bike and seeing if the bulb monitor idiot light goes out like it's supposed to when the brakes are applied. Then unplug the brake light and see if the idiot light works.

I'm guessing that these tests are probably faster, easier and more reliable than trying to find some static tests to perform.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

tinyspuds

tinyspuds
Life time member
Life time member
.75 I’m sure you are right. My rationale with the ‘straight’ relays was to get a hands on understanding of how to test them (should a diagnostic need arise in the future). Interestingly, the first one tested passed a coil test but failed on a resistance test across 30 to 87. So, a useful learning exercise for me.

I will do as you suggest for bulb monitoring as, apart from the brake light switches and bulbs its a pretty much stand alone component. But I’ll persevere (a bit) on the temp unit as it feels like a good thing to understand for future debugging as it is so dependent on a lot of external activity working right too.

Would I be doing this if I could ride? No. But my lack of electrics knowledge is one I’m trying to fix. I may even get to where I can work out how to wire the charging circuit on my positive ground mag/dyno Enfield, which frankly just does my head in every time I look at it  Mad.


Cheers, Stu


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

Dai

Dai
Life time member
Life time member
@tinyspuds wrote:I may even get to where I can work out how to wire the charging circuit on my positive ground mag/dyno Enfield, which frankly just does my head in every time I look at it  Mad.
Wire to negative earth and flash the dyno... problem solved. Very Happy


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

Dai

Dai
Life time member
Life time member
Joking aside, yes; those Lucas switches can be a complete shit to figure out what they're doing.


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

tinyspuds

tinyspuds
Life time member
Life time member
Damn! fried the bugger anyway. 12v to number 9 but 31 to neg terminal of battery. 
Another lesson learnt. I try to get less dangerous each day.


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Expensive way to learn about electronics. Sorry to hear of your module's untimely demise.

K.I.S.S.

Most test procedures are just trying to reproduce the external inputs and measure outputs. The bike itself is the best test fixture that will automatically let you know if your module is working properly.

Modules like the temperature and bulb monitor have really bad documentation and a lot of sensitive parts in them. Even if you can determine what the problem is, you will have a miserable time doing anything to correct it.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

tinyspuds

tinyspuds
Life time member
Life time member
@Point-Seven-five wrote:Even if you can determine what the problem is, you will have a miserable time doing anything to correct it.  
I may not be able to make a determination, but I can bloody well punish the culprits  Very Happy .

I always hate when I break stuff thru stupidity, but live and learn.

But I did get a successful test on all the regular relays so that’s a nice little stash for the sidecar.


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

robmack

robmack
Life time member
Life time member
@tinyspuds wrote:Damn! fried the bugger anyway. 12v to number 9 but 31 to neg terminal of battery. 
Another lesson learnt. I try to get less dangerous each day.
Pin 9 is +ve power and pin 31 is -ve power. How did you fry the module?


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

tinyspuds

tinyspuds
Life time member
Life time member
@robmack wrote:
@tinyspuds wrote:Damn! fried the bugger anyway. 12v to number 9 but 31 to neg terminal of battery. 
Another lesson learnt. I try to get less dangerous each day.
Pin 9 is +ve power and pin 31 is -ve power.  How did you fry the module?
Dunno. I hooked it up the same way as the relay tests but major spark at 9 which I couldn’t repeat. Assumed I’d burnt out the connection and read in a couple of places that I should have just earthed 31 rather than back to the -ve post. I’ll still test it in situ on the bike as recommended.


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

14Back to top Go down   temp switch and bulb monitoring units Empty Bmu Sat Mar 20, 2021 3:01 am

daveyson

daveyson
Life time member
Life time member
Hi tinyspuds upon Sandwich,

Another little test on the bulb monitor unit, after you have extinguished the warning light with both brake levers.

With the ignition still on (or in park position) remove the tail light bulb from the rear of your bike. The warning light should glow. Replace the bulb and the warning light should be extinguished again.

This is a good nifty little safety feature of bricks, the very second your tail globe blows, you get a warning, very important for bikes, and even for cars.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

tinyspuds

tinyspuds
Life time member
Life time member
@daveyson wrote:Hi tinyspuds upon Sandwich,

temp switch and bulb monitoring units 44271


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

16Back to top Go down   temp switch and bulb monitoring units Empty Bmu Sat Mar 20, 2021 3:14 am

daveyson

daveyson
Life time member
Life time member
Love those place names. It's on my wish list to ride down some tiny English country roads and go into a little country town pub.

Of course I should have added that the light switch needs to be on for the test.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

tinyspuds

tinyspuds
Life time member
Life time member
Watched a program yesterday about a ride through the Nullarbor. I have more chance of doing that atm than I do of getting into an English country pub!

The bulb monitoring test is pretty simple for me as all rear end wiring is housed in a splitter under the seat to share power with the sidecar lights. So I just have to pull a connector at a time to test.


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

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