brake lights not working

[azr]

hey all, the brake lights on my new to me 78' TS250 are not working properly. When I turn the key on the rear light comes on very bright, almost too bright for a 6 volt bike, putting on either the front or rear brake does nothing. If I turn off the light (which I can on this bike) and put the brakes on I can see the second filament come on but very lightly. The other thing that happens is when I put a turn signal on and then put the brakes on the the very dim brake light goes on and off like the signal. I haven't started testing the harness or looking at the grounds yet, that'll be in the morning but I though I would throw it out to the 'hive' tonight to get a few ideas. Thanks in advance.

[chuck hahn]

Sounds like exactly what youre suspecting to me.....bad grounds. I would also suggest that while at it, solder all the wire to connector connections to ensure these are strong as well. May look fine but have corrosion and weak spots there as well

Check the proper bulbs are installed too.

[Brendan W]

Bad earth point or wire somewhere near or inside the tail cluster I would say as well. Corrosion at the bulb holder can also do it. Current is having to find alternate routes to ground.

[Phred]

Check the wiring from the tail- signal lights to where it connects under the seat. I had an intermittent problem with mine and discovered that the wire was frayed where it ran under the rear fender. It may dropped from the little clip at one point and may have been chaffed by the tire or had been pinched by the clip. It took a little while to find it as the frayed section was under the clip and not obvious to the naked eye.It was shorting itself out on the clip.

[salty_monk]

Earth fault most likely, it's using the brake filament as it's ground most likely - maybe also a short between the brake & the regular light.

[azr]

Thanks for all the input guys, all I did with her today though was buy some Deoxit and ride it. I'll the garage tomorrow and let you know. One thing I did notice, the front signals have the typical Suzuki grounds, eyelet around the turnsignal shaft etc.., but the rear signals have no ground, although looking at the wiring harness there is no where for a ground wire to go anyways.

[chuck hahn]

Make your own and run the wire up to a hard point on the frame somewhere.

[azr]

All fixed. Pretty simple fix really, the original tail light was smashed on the bike so the PO put another on one that's almost the same and just had to make up some lengths of wiring to reach the harness terminal....the two wires were crossed. I sure like the easy fixes anyways got to learn some of the wiring on the ol' girl so all is good. Took her out for another ride, got it up to 100km today, lol. Sure if a TON of fun this thing.

[chuck hahn]

Cool when its easy and doesnt cost you anything.