My rear brake light stays on?

[Bateman]

My tail/brake light on my 1150GS isn't working properly. It seems to be always on the brightest level, as if i am pulling the brake. If I pull the brake or press the brake pedal, it doesn't get any brighter. But it definitely seems like it is jammed at the brightest setting.

Not being a technical guru, I have so far:

Taken the bulb out and put it back again
Sprayed everything with WD40
Pulled the brake lever and depressed the pedal several times and can hear a clicking (the switch?")
Sprayed everything with WD40 again


So now its time to get my hands dirty and maybe even dig out a multimeter?

Any advice on what to check for would be gratefully received

 

[Bateman]

Just checked some other things - with the light cover removed, if I pull the brake or press the pedal, there is the faintest increased glow, but nothing obvious.

 

[ELIMINATOR]

Servo brakes ? Or not?

 

[John Armstrong]

Tried another bulb?

 

[Fanum]

It sounds like an electrical prob rather than a brake pedal/lever prob- if you can hear the microswitch and see a tiny increase in brightness, it's unlikely eother are stuck 'on'.

Take the bulb out of the holder and clean the contacts with the end of a small flat blade screwdriver- there are two contacts that match up with the two bumps you'll see on the bulb's base.....make sure there's nothing inbetween the two contacts.
The bulb earths through its side, so make sure there's nothing touching between the base of the socket and the side walls.

Try the bulb again.

Next pull out the light reflector and socket assembly and check the wiring on the back- in particular the earth connection....take all connections off (remembering or marking where each one goes ) and clean with emery paper etc.

Try bulb again.

After that, you will be into the realms of multimeter testing, but usually something like this will be cured b the above

There are some odd bulbs out there as well BTW...you have got a standard 5/21 12v stop and tail bulb?
There should be two pins sticking out the side, at different levels from the base.

You can't see the other pin here, it's higher and round the back

 

[Voyager]

It sounds as though you have managed to put the bulb in 180 degrees out of line (I once managed that with a car).

That means that the 21w filament is acting as the rear light and the 5w filament is coming on with the brakes (tiny increase in brightness . . clue ?).

Just check it to be sure - its usually something simple !

Bob.

 

[Marks adventure]

GS RIDER (Bill) has got the same problem, he thinks that it may be the switch on the bars?

 

[Clive795]

I have this problem on an R850R at the moment.

It is the microswitch on the handlebar brake lever. It happened last winter as well and I unscrewed the microswitch and gave it a good soaking with WD40 and it was fine until about a week or so ago.

Mine is currently unscrewed and zip tied to the mirror arm and i just make sure i touch the rear brake pedal every time I brake.

I will give it another dose of WD40 and hopefully it will last another winter.

Clive

 

[DrFarkoff]

Faint increase in brightness

Hmm IMO Bulb 180 degrees out so you're showing the brake's 21 watt filament on all the time for the tail lamp

Then when you use the brake the 5 watt tail lamp filament is increasing the glow

take the bulb out and turn it around and try again?

 

[Bateman]

Thanks to all for the suggestions. A few weeks ago my wife said i didn't have a rear light when she followed me home. So I changed the bulb. As it turned out, the reason i didn't have a rear light was because the bulb had pulled loose. When i changed the bulb, I forced the new one in the wrong way round and, as per Voyager and BeemerJay, it reversed how the light should work.

So, I have put the bulb in the right way round and it works as intended but now it won't stay secure and works its way out a few mm and switches off once i start riding. I fear i may have broken something when I forced it in the wrong way round?

 

[DrFarkoff]

works its way out a few mm and switches off once i start riding. I fear i may have broken something when I forced it in the wrong way round?

The bulb should have 2 pins directly opposite each other (around the bulb, but at different heights up towards the glass if one or both are broken off then it will come loose, If you're in any doubts just change it

You may have pushed the little copper contacts in a bit so with the ignition off and the sidelamp turned off you should be able to move them gently a couple of mm further out so they stay in contact with the bulb?

 

[Voyager]

So, I have put the bulb in the right way round and it works as intended but now it won't stay secure and works its way out a few mm and switches off once i start riding. I fear i may have broken something when I forced it in the wrong way round?

You have probably distorted the bulb holder and the bayonet fitting is no longer gripping the bulb.

Bulbs today don't have the solid pins they used to have in days of old todays just have crude projections so it is easy for them to slip.

Some slight re-adjustment to the bayonet fitting should cure it.

A light coating of Vaseline wouldn't hurt either - with winter approaching.

I seem to spend a lot of time keeping the lights working on our five cars and my three bikes and three trailers.

 

[Possu]

I had the same problem on my 1150GS. The brake lever was dirty around the pivot point & not returning fully outward. Removed it, cleaned & lubed & then refitted, all working correctly again.