Wiring Issue

[sethmcalister]

I posted this over on TRAT too. I started my DIY fender eliminator this morning. Things went really well until it came time for wiring the brake light I picked up from Dime City Cycle. There was no wiring diagram provided with the brake light so I had to attempt to figure it out on my own. There were three wires, black, yellow and red. The old wiring harness I pulled from the stock headlight had black, red and blue.

If I looked at the wiring diagram from my manual correctly, black is the ground, red is the tail light and blue is the brake light. I played around with the wiring form the light to the harness and ended up connecting black to black, red to red and yellow to blue.

I found that with this combination the tail light worked, but when I hit the brake light, the other filament didn't light up - I'm assuming that it should have. I then tried black to black, red to blue and yellow to red and this netted the same result. I ended up with the first method; black to black, red to red and yellow to blue.

I connected everything and taped. When I blew two fuses I realized that the heat shrink wrap that I had used didn't fully protect all the metal so I taped everything separately and then re-wrapped the harness.

I got everything ready for a ride, started the bike up and then found that my tail light wouldn't light up. My brake light worked, but that was it. I pulled the wiring apart again and tried black to black, red to blue and yellow to red to no avail. I pushed the bulbholder out from the DCC light and found that yellow was the ground and black and red were connected to the nodes. I rewired my black from the harness to yellow on the light and tried the other positive combinations and still nothing.

Now i was back at ground zero. I ran and grabbed the old light and connected everything back up the way it was when I cut it, black to black, red to red and blue to blue. Even that didn't give me a tail light - only a brake light. I'll post some pictures, hopefully that will help you guys visualize what I'm seeing.

I don't have a clue what is going on? How does the tail light work and then all of a sudden it doesn't? Is it possible I blew the relay or something? I was thinking the relay was for the brake light though, not the tail light. Any help would be appreciated it.

 

[devo]

Sorry Dude
Sounds like you did it right but obviously something has let go on the way
I'm no sparky, but I would be looking deeper for another blown fuse or a relay.
Or is it possible you pulled a wire somewhere along the way.

 

[sethmcalister]

Sorry Dude
Sounds like you did it right but obviously something has let go on the way
I'm no sparky, but I would be looking deeper for another blown fuse or a relay.
Or is it possible you pulled a wire somewhere along the way.

Well the only piece after the wiring is the connector. Unless there is a loose connection there, bit there shouldn't be since I didn't touch anything there. I'm pretty sure the wires were connected properly. It is weird that even the old.light hiding doesn't work now though either. I'm pretty sure the relay is for the brake light though and not the tail light....right? The fuse is definitely good, otherwise the blinkers and brake light wouldn't work.

 

[The Seeker]

Just a thought here, but did you try a new double element bulb? When the fuse blew, it may have also melted the filament for the tail lamp.

Here's what I would do without a wiring diagram......before attaching wires together, I'd use one of those circuit testers that light-up inside the handle and attach the alligator clip to a ground. Then touch the probe to the bare wires one at a time. With the ignition on, your tail light wire would light the lamp inside the handle and the other two would do nothing. Now you know which one is the tail light wire. Now activate the brake and touch the probe to the other two wires. The one that lights the lamp inside the handle is your brake light wire. Obviously, the third and last one is the ground.

 

[sethmcalister]

I didn't try a "new" one, but I did grab the bulb from the old light and still only the brake light. I have a continuity tester so I can test that tomorrow and hook the new light to the battery to figure that setup out. I'm crossing my fingers that works becuase I've no clue if it doesn't.

Sent from my ADR6400L using Tapatalk

 

[avion]

I wouldn't think that it was a relay, one that it's normally just a make or break switch on the front and rear brake levers. Secondly, the fuses should protect a relay anyway.

I would start off checking every wire for a short on the frame or good earth point. Check both harness side and the new globe holder side for shorts.

After that, I would start measuring voltage outputs on the wires, you can permanently engage the brake light by holding the front break in with some tape or zip tie.


hth

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