brake indicator light turns on, stays on

[puftas]

Having a new issue with my 77 xs650D
When I start it, indicator lights on dash seem fine, but after a few minutes the red BRAKE indicator for the taillight comes on and stays on. Brake light functions normally, just no longer indicated by the red light coming on cuz it's already on.

Is my bike trying to tell me something? or is this just a wiring issue in the console or something. Haven't been messing with it recently so seemed odd.

 

[Michaelo]

Hi Puftas....mate have a look at a wiring diagram in the tech section for your bike, brake indicator light on usually means a blown bulb or incomplete circuit, so clean terminals (bulb holders) and check your wiring, it can be found but you will need to eliminate the obvious first..
There are plenty of others who know wiring way better than me so they might chime in here too....

Mick

 

[rsor]

Is it possible that it is the rear brake lining warning light that is going on?

 

[XSLeo]

I don't believe the red light was ever a brake light failure warning. It is a brake lining wear limit light. When the shoes wear beyond a certyain point a switch on the brake plate turns on the warning light.
Leo

 

[weekendrider]

The 77 had a switch in the hub plate?

 

[rsor]

My 1976 has that switch.

 

[5twins]

It was discontinued in '77 as far as I know. Maybe some early made '77 models still had it but most didn't. Just look at your rear brake plate, see if it's there. What you're probably dealing with is a rubbed through wire shorting out, creating a ground. The light bulb is supplied constant power on a brown wire from the key. It is activated by the light checker turning the ground on. The ground carrying wire running up to the bulb is a white/green. It runs to a 3 wire plug under your seat and that connects to the light checker. I'd check that W/G wire along it's entire length. It may be rubbed bare somewhere and grounding out on it's own.

 

[Michaelo]

You are onto it 5T

 

[puftas]

sooooo, went looking for shorts, didn't have to look far. First I found a giant blue-crusted burn on the positive side battery cable where it feeds out of the battery box, then, following that found this!

black ground wire burnt along it's length, fusing n melted harness from rectifier, up to cross under the frame, and all the way back to the pin-connector to the rear lights... So buying a new harness. rectifier actually seems to test okay. even though the black wire is burnt on it too. I might buy the combo reg/rec unit for good measure. Wish I had the money to do a PMA at the same time.

But real question is: did I find the problem where it had burnt to the frame by the battery? looked like a rubbing situation. I will be opening up the headlight and tail light connections to install the harness, so will check them, but what else do I need to be thinking about? I'd prefer to do this only once.

 

[puftas]

oh and this bike doesn't have a break wear switch. I understand 77's had 2 slightly different productions? I don't have my engine # in front of me.