This one is really weird. On a 1993 R100GS/PD the rear running light does not work. Brake light works, and the Parking light works. That's the rear light on the first position of the key. But when I turn the key to full on it does not light up. Also does not work when the bike it running.
Checked the fuse, OK, but it can't be that anyway since the Parking light works. I just replaced the battery and noticed the problem when checking all lights. I don't think the battery has anything to do with the problem, but that's when I noticed.
I'm stumped. thanks
@8166 By the Parking light I mean the rear light activated by the key in first position. So the bulb is fine. I have a non standard bulb. It appears to be a halogen bulb put in by a previous owner. When I test the gray/black wire to the rear light it sends current only in parking position (so the wire is good). Nothing on running key position.
The thing is the key works fine in the second position, the running position – except for the rear light. Why can that go away?
FIXED - well, really user error. I realized it has European switching gear so the rear running light goes on with the main lights only.
The thing is the key works fine in the second position, the running position – except for the rear light. Why can that go away?
Possibly for the exact reason you were already given.... corroded contacts inside the ignition switch.
The German ignition switch is not the simple ON/OFF device you imagine. Inside the switch, some fairly complex mechanical switch gear allows the logic of powering the Emergency key position you keep talking about. In later years the logic became so complex that an extra relay had to be incorporated into the wiring harness. All this is so that you can park on the shoulder of the road and leave your tail lamp ON, without leaving the headlamp or ignition ON.
Inside the switch, all the internal conductors are made of brass. That naked brass will corrode due to time or rain, and can be accelerated by the pH of washing soaps. So you have naked brass being used to make electrical connections, trying to survive possibly 100,000 ON/OFF switching cycles, and it's up against nearly 30 years of aging, rain water and pressure washing with detergents. I'd say you're pretty lucky it made it this far !
If the suggested DeOxIt spray doesn't work, then I invite you to pop the back off your ignition switch and then sit there in total amazement, wondering how the Germans ever got all 397 springs, balls, levers, contacts, latches, and other pieces into that small space. Trust me. It will be a real education.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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