headlight gremlins

[oldbiker648]

I'm no electrical guru, and my '78E is the first bike with a fairing (Vetter) which I have ever owned. My problem is this, running lights on the fairing work, but headlight doesn't, unless I have both the front and rear brakes activated simultaneously. The rear brake will light up the brakelight, but the front won't. Looks like I have a short, possibly the front brake switch wire, but by itself, appling pressure to the front brake lever will not light up the headlight, I have to have the rear brake pedal depressed as well. The fuse block is history, and I have a series of wire nuts and glass fuse holders in place under the right side cover, all of which check out to zero ohms resistance, indicating continuity is OK (BTW, I have a new fuse block from TC which I plan on installing soon). The connector is a 9-pin assembly with no obvious corrosion or bent pins. At idle, or with the key on, I get continuity on only one circuit through the fairing connector. Wiring diagram won't work unless I trace the bike side of the fairing connector harness back to each wire. Someone out there with a strong electrical background can probably save me some busy work, at least I hope so. I have done what I think are the obvious things as far as breaking connections, wiggling and pulling on wires in case I have a bald spot somewhere, all to no avail. Help!

[TopCatGr58]

Hey John,

A review of the wiring diagram shows that the front and rear brake switches are powered from a common "tan" colored power line which also powers the horns, the fuel gauge, flasher relay.

Apparently the PO cut the tan wire that goes to the front brake switch, and then spliced into the wrong (dead)end of "tan" wire that goes to the front switch, and so there's no power to that end of the tan wire until you hit the rear brake switch which energizes the green/yellow wire, and it then flows backwards to the front brake light switch, and then when you activate the front switch, it completes the circuit to that tan wire that is probably spliced into the headlight?

That's my idea of what's wrong!?
T.C.

[yamarider]

If all else fails on the headlight problem, just direct-wire the thing through a simple heavy-duty on/off switch that you can install in the fairing. Radio Shack is a good source for switches.