I'm banging my head on the wall on a problem over here. I'm trying to track down an electrical issue I had with my front brake switch wiring wherein I fried the switch when I connected a battery and turned on the key. Okay that's fine, I caused a short, no problem. It's my understanding that the brown wire that connects to the front and rear brake switch carries current constantly and when you pull in the brake lever it completes the circuit and the current flows to the tail light.

The issue is that now the brown wire that connects to the front and rear brake switch is showing both 12.3 volts of current against the battery negative AND it grounds out to the battery negative at the same time. I test for voltage, I see 12.3 volts, and then I switch the voltmeter to ohms and it beeps and reads 0.00 ohms. I'm confused. Can it be both ways? I tested it to the frame and it beeps. I tried the other brown wires throughout the bike and they too read both 12.3 volts and ground out at the same time. What is going on?

The wire grounds through what ever it's supplying voltage to, so any lights that are on or electronic gizmos in use the wire will ground through.

Rick

Yes , the brown wire will always show 12v as the power supply , the other wire going to the switches are black and should show continuity to the frame and neg battery.

The switches are normally open (no continuity between the 2 wires) and then close when activated , thus grounding the circuit which allows current flow ( lights light up ). The lights are like a resistor , only takes/allows a certain amount of current flow and that's it . If there is a big draw beyond whats needed for the bulbs , there is a direct short that allows more draw than the lights , and it's upstream of the bulbs , otherwise it couldn't draw so much .



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Thanks. I did a side by side comparison with my xt600 and got the 550 to behave the same. Tail lights work now and don't smoke wires anymore. Great.

I'm still working out a flasher issue though. I'll preface by saying that I think it's the control switch. When I signal left with the control switch the left flasher does what it's supposed to do. When I signal right the right flasher only turns on when the switch is pushed fully and then goes off and doesn't flash. However I can see the other lights on the bike subtly blinking as if the flasher relay is working but the flasher light isn't working. I opened up the control switch and sprayed Detoxit onto the contacts but nothing changed.

You should be able to test the output wires and test for power coming out when switched to the right , and then tested at the flasher unit for power as well . Basically following the juice and ground from start to finish , testing at different spots till one doesn't check out correct . When I installed LED rear blinkers my e-start developed some weird lighting issues till I ran separate ground wires to each circuit rather than the sharing like it was originally .



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I managed to track down the gremlin in the wiring. The dark green wire that carries current from switch to the right blinkers was, like so many other things on this bike, shorted out. That explains the dimming lights every time the flasher relay fired for the right blinker. I attempted to track down the short but after removing 50% of the wiring harness wrapping I gave up and just ran a new wire down the harness. I also made a new ground point for the blinkers. I rewrapped the harness and tidied up the wiring behind the headlight and now it all look and works great. Thanks for the help!