Couple of times now, I've returned home to find my topbox lid laying open......maybe I didn't get it latched, Maybe I failed to close it at all before leaving?
At any rate I'm thinking about an alert system so if it comes open I'd know it.
I'm thinking simple.....
Does this work????
It appears that the bulb monitor red dash light would come on if the tail light failed while moving. Does anyone know?
(I haven't yet disconnected the bulb to see if the W/L will come on without having to re=start the engine???)
If so, I thought it would be fairly simple to run a short jumper from the tail light wiring up to the topbox & across a 20W magnetic N/O switch. Idea is, the box top comes open, the tail light would go out and bring the dash W/L on.
Would it work?
regards, ibj...

good luck finding a 20 watt magnetic switch ....they are normally reed switches rated for just a few milliampps .....any more and they weld together

surely you mean microswitch to the lid that could well be rated for a few amps.

just a thought

"I'm thinking simple....."
Looks far too complicated to me. I just double check mine every time I stop - now that is simple!

even with the specifications to 20 watt i warn stongly against such a device

if you look at the details the max current is 1 amp dc

you must remember that any .....i repeat..... any globe... has a verry low initial resistance whilst it turns on ...this in fact can exceeed 8 times the once ACTIVE AND LIT glowing current required

in a headlight relay type situation even rated at 20 amps (relay )_you will still see pitting caused from a modest 5- 7 amp load such as a headlight turning on

automotive manufacturers already know this fact ...and if you look deeper you will find the max limits far exceeed the constant current ratings ...well in any "respected " brand of relay ...those cheeap and nasty chineese versions contacts are less than 1/3 the contact area of a "normal " type device ....dont ask me how i know

if you must proceed with this type of switch

treat it as an experiment ...it may work for a while ,,,but as a reliable device for the 10 watt tail light globe in a volatile and vibration persistant ....and unreliable magnetic field strength-distance ...application ...forget it ...

just an opinion

Well mate sounds to complex to me, but the Lincoln bomber was an electrically controlled nightmare according to my old uncle, suggest a couple velcro straps glued screwed or riveted to secure the lid reliably when you want it shut. Good luck.

ibjman wrote:Couple of times now, I've returned home to find my topbox lid laying open......maybe I didn't get it latched, Maybe I failed to close it at all before leaving?

If you mean the original bmw top box, I too had the same problem ...... ended up buying a Rjays topbox

The one that came with the K75 my wife rides came open and was very quickly replaced and flogged off on fleabay for a lot more than it was worth. It was like brand new and came open just about every time it wasn't locked.
To me they never quite look right. BMW usually get it right looks wise but that small top box just didn't make it.

Maybe you could use something like this?

It's just a two-wire setup through the ignition switch to a bulb on the handlebars. If the magnetic contact between the two parts gets broken, your light goes out...

http://www.kasonind.com/index.php/products/lighting_and_electrical/electrical_supplies/1967-8-door-open-sensor/

The first of the 21 litre top-boxes I owned was way back in 1988. It bounced open shortly after I fitted it and I lost some of the contents before I noticed that it was open.

I soon realised that adjusting the lock properly via the large plastic nut is important.

Secondly, it helps to lock it. I know that can be bit of a faff if it isn't keyed the same as the ignition but re-keying it is simple enough.

Lastly, the fit is important. That's the fit of both the plate and the top-box to the rack. The foam on the plate turns to dust with age and along with a loose fit on the rack, that will encourage the lock to rattle open.



Some 3M self-adhesive foam judiciously placed on both the plate and the underside of the box where it is in contact with the rack overcomes the problem.







Never had one come open since doing this.

I will revisit the foam on the bracket & under the box. Seems as if the looseness or rattling around of the box on the bracket could cause some momentary torsional deformations of the materials so as to cause the latch to become out of alignment with the striker, resulting in a closure failure!
Curiously, though it was thought that actually locking the release mechanism results in a lessening of the occurrences.
This would leave me to conclude that the failure is resulting from an physical retraction of the hook rather than a movement (twist) of the whole lack assy. in the plastic casing.
As for the alternative concept of wiring up an idiot light to the dash, that negates the original wish to do it with a minimal amount of wiring complexity.
All that said, Charlie (who's opinion I deeply respect) advises against the idea.
If I read the suggestion correctly, he also advises against a similar switch triggering a relay?
Thanks again, ibj...

not at all ibj ....just to rely on a reed type switch is my issue

a simarly placed microswitch would work well and be reliable as it has flexability in the tolerances of the actuator and the switching contacts would provide reliable operation .

i do have an adverse thought about using the tail lamp as the switched device though ...i think any thing with safety of the rider or bike in motion shouldnt be played with adhock .

it is a good idea for utilizing features of the system in place by the designers .....but as i said i have issues with the safety aspect

if you could switch in some resistance that kept the globe alive but dimmer .....and get the bmu unit to see it as a fault condition that would maybe a better aproach ?

How about the roller/flexi arm rear brake light switch from my junked K75 is it NO or NC?

How about a mercury switch?



Didn't some Volvos have them fitted to their bonnets (hoods), so when you open the bonnet the light came on to illuminate the engine bay? Some Chrysler's (US cars) did too I think.

ibjman wrote:How about the roller/flexi arm rear brake light switch from my junked K75 is it NO or NC?

yes a much better option for a switch ..... they are n/o

blakey a good switch for limited movement and angles good for a car bonnet lid ( or a moovement switch on a bike bugular alarm, where its connected basically to the frame ) ...but being a glass envelope is a pain , that lid flips right over 180 degrees mate

still think i would put a warning lamp-led on the rt dash for this ...3mm hole and nothing else visable and a 2 pin quick disconect electrical socket for when box is remooved , using a switch that was n/c