Rear tailight problem...

[wuzred]

Didn't see an existing thread decribing my problem so maybe it a first although I doubt it.
When I go to work in the morning it's always dark and at least half the time I won't have a tailight(brakelight always works) for the first couple of miles. Then it will come on and stay on. How do I know this while riding you ask? Because my instrument lights also do not work when the tailight is out.
Any suggestions, fuse, relay, I am not electrically inclined enough to read the wiring diagram and have been known to let the smoke out of a wire or two.

Thanks,
BIll

[20774]

Bike? Year? Most likely the problem is a common ground. You'll need to see a wiring diagram for your bike and identify the lights that work intermittently and see how their grounds are connected. Then find the ground, clean the corrosion, and tighten the connection.

[wuzred]

Sorry, '82 R100RS.

[ccolwell]

I agree. Corrosion at the ground or another connection. Check the multiconnector under the seat and the blade connectors in the tail light unit. It's worth taking the bulb out and checking it too.

[wuzred]

I have cleaned the multi-connector under the seat but figure it must be firther upstream since the gauge lights are affected. I'm not sure if it's my imagination but it almost seems like a heat issue, being that a few miles down the road it always comes on. But I can't determine any difference between summer or winter.

[tghsmith]

look in the tail light unit and the bulb contacts, the system is wired if your tail light is out it lets you know by having the guage lights out(crud, corrosion and drirty contacts will act just like a bad bulb , leave the lense off over night and wiggle the bulb in the morning to see if that makes it light, after this then you start messing with relays and other connections...

[dduelin]

My '81 R100 has an in-line fuse that once had some corrosion on the fuse ends causing the instrument lights and the rear running light to work erratically. I believe the wire is brown coming off of the terminal strip in the headlight shell.

[amiles]

My ignition switch was going bad & I had this same issue. Try wiggling the key a bit in the "Run" position and see if this helps.

[lostboy]

Check the parking light fuse and it's mounting points. It's the one associated with the grey wires.

[wuzred]

I think I might have found the problem. Last night cleaned the 6-pin connector up by the headlight housing but still had the problem. So I thought maybe it was the wiring to the remote fuses so I went into the headlight . While pushing/pulling wires in there with the ignition on I bump a wire going to the light relay and the parking light came on. Touched it again, same result. After putting a new connector on the yellow/white wire and re-assembling everything I've got a tailight now. The proof will be riding to work tomorrow. I'll let you know. Thanks for all the input.

[535is]

Let's cross our fingers and hope the front taillight doesn't go out next ... :whistle

[wuzred]

So far, so good. The ride in this morning I had a taillight & dashlights all the way.
Life is good.