Brake lights stuck on

[stolzy]

All of a sudden my brake lights are permanently on
Checked the pedal and lever switches and they are OK, levers are fully home.

If I disconnect the switches at the connector on the right side of the bike the brake lights stay on.

If I remove fuse 1 (brake light) the lights stay on, if I remove fuse 2 (tail light) the lights go out.

Seeems like they are getting power from the tail light circuit - or is that stupid?

They were working fine aweek ago and I've done no dabbling since. I have been riding in torrential rain a fair bit.

Anyone have a clue?

 

[Mr K]

The brake light filament may have snapped and fallen into contact with the tail filament.

 

[John Armstrong]

Some muck between the tail and brake light connections, might even just be moisture. I'd give it a good drying out with a hair dryer, and then spray some contact cleaner around. Other possibilities I'd guess are the cables for the two haven't chaffed and giving you this problem, or there's a bad earth.

 

[JoeC]

Could be that the normal rear light filament has blown and the default is that the brake light stays permantly lit in order for your rear to be seen. BMW has designed it that way.

However, I had a similar situation whereby the brake light stayed permanently on once the bike had been used for a while i.e. it was OK at beginning of all journeys but was permanently on at the end.
Turned out to be a sticking front brake microswitch. A squirt with WD40, a wipe and further squirt of the microswitch sorted that one out.

 

[DrFarkoff]

Change the bulb for a start

Disconnect one brake switch at a time and see if it goes out

The may have rubbed thru to the frame somewhere and are earthing out
or if when you disconnect a switch you may find it's shorted due to being full of water ?????????

HAve fun

 

[stolzy]

OK, should have added the following:

The bike has LED tail/stop and a brake light modulator which (I have have just learned) takes the brake light feed from the tail lamp circuit (hence the behaviour of the fuses.

 

[stolzy]

Turns out the brake light modulator is faulty - I connected the brake lights without it and everything was fine.