As usual, I'm having problems w/the brake light on my 2005 TE450. I've previously written about how the wiring is somewhat home-made on this bike by one of the previous owners. I'm number 3. I learn electrical as I go and haven't learned that much to this point. I'm begging for help as this issue is driving me crazy. I don't want to get pulled over on the road for not having the brake light. This winter, I worked on it and got the tail light working all the time when the bike runs (no key switch on this bike). Also, I managed to get the brake light working when the bike runs with a new wire from point a to point b. After a few rough rides early this month, the brake light stopped working. Here is what I found so far: 1. Tail light has three metal contacts - 1 for tail light, one for brake light, one for neutral. Both filaments on the bulb are good. 2. The tail light still works when the bike runs. 3. The front brake switch wires, when touched together, turn on the brake light. I think I have a bad front brake switch because when I pull the lever the light doesn't light up. When I cut the wires off the switch and touched together, without and with the bike running the brake light comes on. 4. When I step on the rear brake pedal, the light doesn't come on, without and with the bike running. 5. When I pull the wire/connector off of the brake light contact at the bulb and hook up the voltmeter and step on the pedal, I get 12-13 volts on the end of the wire (it ramps up from 8 or 9 volts to 12 or 13 volts) with the bike running and not running. Before I step on the pedal, the meter actually reads 0.54 volts. 6. When I reattach the wire to the connector at the brake contact and touch the lead to the contact and read the volt meter, it goes to 0.00 with and without the bike running. 7. If I don't reattach the wire to the contact but simply touch it to something steel the same thing happens, it goes to 0.00 on the volt meter. 8. I assume all of this means I have a bad wire somewhere. Which wire should I trace? The wire from the rear brake switch to the brake light contact? Do I have a cut in the wire somewhere that touches metal? Broken wire maybe? I'm assuming this is the wire to check since all of the other wires/lights work. The blinkers also work for that matter if that means anything. 9. I started chasing wires but eventually they get buried/bent/taped together so before I perform surgery I just wanted to solicit some expertise. Sorry, for the long post but wanted to be as specific as possible. Hopefully, this helps somebody else, too.
Update I have traced every wire and cut off all connections so I'm down to simple wires I'm checking. Problem is not solved but here is what I found: 1. If I have the ground connected to the bike or the battery and the tail light assembly and touch 12 volts to the brake light contact, it lights. The 12 v is run directly off of the hot wire, not through the brake switch. 2. If I run the hot through the switch and keep the ground connected, the light won't light. In addition, if I take the wire off of the light contact, I don't get 12 v reading out. 3. However, if I disconnect the ground, and apply the brake and check the voltage at the other wire off of the switch, I get over 12 v. I assume that means the switch works. The other wire off of the switch is not connected to the light assembly when I do this check. 4. It seems that once I connect the wire to the light contact through the switch, something goes wrong and cuts out the 12 v to the light. 5. Even if I try to 'fake out' the light and run wires through the front brake wires that turn on the brake light, the same think happens, no 12 v going to the bulb. I have no clue what is going on and how to even get around it.
If it makes you feel any better I think that the wiring on these bikes looks home made - from the factory, not just yours. It reminds me of the wiring in a cheap chinese car, endless tiny individual wires going in every direction. Its kind or funny how we use a 7mm thick high grade aluminium bash plate to protect the crank case, but there are single tiny wires designed into the most exposed and vulnerable areas. No idea on your issue, though I had a similar prob but i fixed it by tightening the spring that links to the switch on the brake pedal. But I think that more is happening over your way. Im currently frustrated with some electrical issues on my machine, cant pin it down though..
Update 2: I removed all old wiring for the rear brake light switch and the front brake light switch. I connected the rear brake light switch wiring to the high beam hot wire. It works now as long as I have the high beam slider switch in the right spot. Don't know why or how, but I'm leaving it like this for now.
