rear brake light problem

[steveh]

Just wanted to see if anyone has any further ideas re a problem I have with the rear brake light staying on.

To date I have:

1. replaced front microswitch
2. cleaned up foot switch
3. replaced the rear light cluster
4. changed the bulb
5. Installed a rear LED
6. checked the handguards

The light still stays on!!!!

There appears to be 4.5v through the contact at the rear light cluster where there should be none (i.e. with the brakes off) hence the light staying on.

Any ideas before I take a trip to the dealers?

 

[Demongroover]

Faulty foot switch?

 

[shugie]

It used to be that the ECU would send a low voltage to the brake light filament if it sensed that the rear light was not working.

Is there 12V across earth and the rear (not brake) light feed wire? If so, stick a bulb across and see if it lights. If it lights, what happens to the 4.5V going to the brake light?

My guess is there is some sort of problem with the rear light circuit.

 

[steveh]

It used to be that the ECU would send a low voltage to the brake light filament if it sensed that the rear light was not working.

Is there 12V across earth and the rear (not brake) light feed wire? If so, stick a bulb across and see if it lights. If it lights, what happens to the 4.5V going to the brake light?

My guess is there is some sort of problem with the rear light circuit.

Thanks for the reply, the rear light (not brake) has 12v and is on however there is a constant 4.5v on the brake light including when this light is on.

 

[Deleted account 190920001]

there is a resent post here with a similar problem and the dealer reckoned it was something to do with the instrument unit. Sounds a bit odd to me but maybe worth looking up the thread.

 

[Deleted account 190920001]

just found the thread, it looks like a different problem but here it is anyway http://www.ukgser.com/forums/showthread.php?t=258486

 

[Grey Beard]

I am relatively new to motor bikes so have not yet had a good look at the electrics yet, but this problem (if like a car) sounds like an earth fault. I would suspect/be looking at the earthing/ mounting of the rear tail & brake lights. Quite a common problem with cars. I presume that the brake light is not on when the lights are off/ignition off.

Grey Beard

 

[steveh]

all fixed

i purchased an LED rear light as this should of worked thanks to the advice of steve at motoscot (based on the low voltage not switching the LED) however after all the testing earlier in the week the handlebar switch was loose so when I fitted the new LED rear it still didn't work. Adjusted the switch and it all works fine now.

A bit of a work around but no more rear bulbs suits me just fine. The LED rears also send the code to tell the canbus to turn out the idiot light on the dash too.

God knows what the core problem could be....loom, controller...expensive either way !