When I apply the brake (front or rear) my volt and oil pressure gauges peg. Brake light/tail light works. Doesn't seem to be any dimming of the others lights. Plug seems to be okay. Have traced the gauge wires they seem to be okay. Don't know what colors the brake wires are. Attempted to follow the wiring diagram but can't seem to find the brake wiring.
I'm sure its a simple short just don't know how to find it.

Roach

 

When you say "peg", what exactly do you mean? Do they drop to 0 or peg to 18V?

The Orange wire drives both the volt gauge and most everything else in the faring. A dirty connection will cause problems like the volt gauge (and everything else) dropping considerably voltage when under load. And don't forget the air anti-dive valve. That is run off the brake light circuit.

 

An FLHS doesn't have a voltmeter or oil pressure gauge! So they have probably been added at some time. I would check them and their wiring before looking any closer. Do you have the factory service manual, or an aftermarket one?

 

Thanks Doc H. The volt meter and Oil pressure gauge drop to "0".
GR you are correct sir, the FLHS does not have those gauges. I added a fairing with the gauges in it several years ago. Yes I do have a factory service manual. I have attempted to use the
wiring diagram to trace the wiring from the brake switch to a common plug that would affect the gauges.

Roach

 

Check the ground between everything in the fairing to the rest of the bike. Run a jumper wire to a known good ground to test.

 

That suggests they are losing power, perhaps a poor contact or ground. Many years ago I chased an occasional problem on a BMW and eventually found it, thanks to a friend wh knows his electrics better than I do. We found a loose connector which only failed to conduct when pulled in a certain way. Could be you have to hunt down something like that. Old electrics can be devious things to sort out!

 

Thanks for the help grb.
I hate wiring ghost. I know just enough to get in over my head. I will continue the search.

Roach

 

Chasing gremlins such as this is a damned tedious business.

 

Was it always like this or is this something new?

 

Follow the orange wires to the breaker and jump across it.