Electrical Woes

[Matt Chapter]

So, long story short, I melted the wiring harness and left hand switch assembly.. always use a wiring diagram and the correct parts when making repairs.

I've replaced the switch assembly, main wiring harness, and the head light relay.  When I turn on the ignition I get no headlight or tail light, and the turn signals and brake light don't work.  The dash lights work fine, and the starter button will turn over the motor, so I know the battery is ok.  The bike in question is an '86 R65.

Is there anything other than a mismatched connection that would cause this?  I think I've got the wiring harness correctly installed because it's color coded, and all the connectors are pretty much different shapes.  I verified that the replacement switch assembly was for the '85 to '87 R65s, although I'm not sure how to do the same with the wiring harness since I bought it used.

There is one connector that is not hooked to anything else, but I can't figure out where it might go, and it seems like the old harness was the same.  It's a two wire, green/black and brown, which is the brake light and ground, according to my wiring diagram, but both brake light switches are already connected appropriately, and this connector doesn't reach either of those places, so I'm stumped.

Thanks for any suggestions.  (Laughing, while possibly appropriate, isn't helpful!)

[Patrick_Krivacka]

I don't know if I have much to offer besides sympathy, but having just chased down an electrical problem, I know it can be annoying.

I replaced my main wiring harness and relays and such, only to discover that the wires coming off the right handlebar switch were completely melted together. So I guess if I have anything to offer--don't assume that the rest of the harness are fine ( assuming that you are! ) If you had melting in one section, I would consider the rest suspect. Good luck

[Matt Chapter]

If you had melting in one section, I would consider the rest suspect. Good luck

Indeed, I had melting from the end of the handle bar to the headlight and then to the relay ... the three end points of the harness.  Luckily I found a used one from re-psycle for "only" ~250$ instead of the 1k$ the dealers wanted.  Add in a new euro left switch assembly and a new relay and shesh ... I hope I'm done buying parts to get this fixed.

[Patrick_Krivacka]

did you ever figure out what cause the melt down? in my case it seems to  have been age. I guess. Anyway, the old dog runs well now. Hopefully one of our more knowledgable members will chime in.

[Bob_Roller]

How many wires do you have connected to the positive terminal of the battery ?

There should be two, one large diameter black wire, it goes to the starter, there should be a smaller diameter red wire, it provides power for all of the circuits of the bike .

[donbmw]

Check fuses

Don

[Bob_Roller]

The head light circuit is not protected by a fuse, it's a main suspect for wiring harness 'melt downs' .

[Matt Chapter]

The old headlight wiring had frayed and broke at the headlight connector, I had replaced the connector with a standard 3 prong automotive light fixture (which worked for quite a while) but then the main beam was dim and the high beam was slow to change back to the main beam.. it was during that troubleshooting that I melted the entire works.

I've replaced both fuses (I bent one while installing the wiring harness).  And I do have two wires on the positive terminal, a black one to the wiring harness and a thick black one to the crankcase (for the starter as was mentioned).