No Tail Light

[TripleKing]

After fixing my over-charging problem on my 89 750, I installed a mini voltmeter. To get power to the three-wire switch, I ran the power wired to the extra connector coming out of the harness, near the right turn signal. All was well, until today, when my gauge stopped working on my way to work.


I checked all my connections at work, but still nothing. I checked the power at the connection and there was none. I also discovered that my tail light stopped working. I check fuses, but they all looked good. I swapped each one, but no joy.

I have no power to the circuit that powers the tail light. However, when I apply the brakes, both filaments of rear bulb light.

Also, I checked the lead at the front of the bike and I get power, intermittently, when have the right turn signal on, but the gauge and the tail light to not light when the turn signal is flashing.

All other lights work as they should, including headlight and gauge lights.

I am at a loss.

Edit: Went to check again. Now when I hit the brakes, I get one filament (dimly), but now my voltmeter comes on when I apply the brakes. Still no tail light. When I remove the bulb, I get no power to the voltmeter.

[Kreylyn]

After fixing my over-charging problem on my 89 750, I installed a mini voltmeter. To get power to the three-wire switch, I ran the power wired to the extra connector coming out of the harness, near the right turn signal. All was well, until today, when my gauge stopped working on my way to work.


I checked all my connections at work, but still nothing. I checked the power at the connection and there was none. I also discovered that my tail light stopped working. I check fuses, but they all looked good. I swapped each one, but no joy.

I have no power to the circuit that powers the tail light. However, when I apply the brakes, both filaments of rear bulb light.

Also, I checked the lead at the front of the bike and I get power, intermittently, when have the right turn signal on, but the gauge and the tail light to not light when the turn signal is flashing.

All other lights work as they should, including headlight and gauge lights.

I am at a loss.

Edit: Went to check again. Now when I hit the brakes, I get one filament (dimly), but now my voltmeter comes on when I apply the brakes. Still no tail light. When I remove the bulb, I get no power to the voltmeter.

There is a small ground wire lead off the battery post. That has a connector just a few inches from the battery post. Check it, and follow the wire, check/clean the contact point for that ground.

Krey

[TripleKing]

There is a small ground wire lead off the battery post. That has a connector just a few inches from the battery post. Check it, and follow the wire, check/clean the contact point for that ground.

Krey

Will do. I also picked up a new bulb, just in case something shorted in the bulb itself.

One question: Would a bad ground off the battery (I know which one you mean) affect just that one circuit?

[Kreylyn]

Will do. I also picked up a new bulb, just in case something shorted in the bulb itself.

One question: Would a bad ground off the battery (I know which one you mean) affect just that one circuit?

The system circuits are split. There are other items on that circuit that you may not have noticed being an issue. I don't have a specific list atm. But it's a start.

If that isn't the issue, I'd start back tracing the wires and connections with a volt meter till you find power.

Krey

[TripleKing]

If it is not a short in the bulb, it would appear to be a problem at the fuse box. In fact, I tested the tail light connector at the tail light (before the second problem of the brake light lighting the meter/running light lighting when the brakes are applied. It appears that the brakes are now lighting the running light circuit instead of the brake light circuit (it lit both when I first started checking). If a bulb is not in the socket, neither the running light nor the brake light circuit has power beyond the tail light connector. The system is reacting like Christmas tree lights that need a bulb to create continuity.

Very weird.

Edit: Looking at the wiring diagram, the only place where the brake light and running light circuits come close is at the tail light. It could be that there is a short in the tail light socket or in bulb itself.

[TripleKing]

The system circuits are split. There are other items on that circuit that you may not have noticed being an issue. I don't have a specific list atm. But it's a start.

If that isn't the issue, I'd start back tracing the wires and connections with a volt meter till you find power.

Krey

Cleaned and checked all connections, disconnected the voltmeter and changed the bulb, no difference. When I left the house, yesterday, everything was working fine. Then I lost power on the running/tail light circuit (brown wire), but when I applied the brakes both filaments lit. Now, my brake levers light up the brown wire, except at the tail light and the brake light circuit is dead.


Edit: The plot thickens. Now, when the license plate light is unplugged, the meter and the brown wire at the front if the bike get power. When I plug in the license plate light, I lose power to the brown wire and the meter. When I unplug the license plate light, the meter usually comes on, but sometimes I have to apply the brake to get the meter to turn back on. Under no circumstances will the tail light come on.

The wiring diagram says that what is happening is not possible. Grrr!

[TripleKing]

OK, I am officially screwed. By plugging in or unplugging various connectors or even the tail light/brake light bulb, I can make the license plate light stay on, as normal, or I make it and everything else on the brown wired light with the brake light. I cannot get the brake light to come on at all and the tail light will only light with the brake applied and all connectors plugged in I have checked the wires in the harness and the wires on both the tail light/brake light fitting and the license plate light fitting. I cannot find a problem. All was working normally, until Wednesday morning. According to the wiring diagram, the only things on the brown wires are the tail light, the license plate light and the unused jack at the front of the bike, which I use for the voltmeter. Also, disconnecting the voltmeter does nothing to change the situation. I can only surmise that it is the tail light/brake light socket or wiring that is the problem.

[Kreylyn]

OK, I am officially screwed. By plugging in or unplugging various connectors or even the tail light/brake light bulb, I can make the license plate light stay on, as normal, or I make it and everything else on the brown wired light with the brake light. I cannot get the brake light to come on at all and the tail light will only light with the brake applied and all connectors plugged in I have checked the wires in the harness and the wires on both the tail light/brake light fitting and the license plate light fitting. I cannot find a problem. All was working normally, until Wednesday morning. According to the wiring diagram, the only things on the brown wires are the tail light, the license plate light and the unused jack at the front of the bike, which I use for the voltmeter. Also, disconnecting the voltmeter does nothing to change the situation. I can only surmise that it is the tail light/brake light socket or wiring that is the problem.

Might be time to buy a roll of harness wrap tape (don't use electrical tape!) and start unwrapping the harness. There is a fault in there somewhere.

Krey

[TripleKing]

Since the problem seems to be in the tail light socket. I am going to buy another one and try it

[TripleKing]

Might be time to buy a roll of harness wrap tape (don't use electrical tape!) and start unwrapping the harness. There is a fault in there somewhere.

Krey

Power is jumping between the white/black brake light wire and the brown tail light wire. In fact, it seem that because of tail light headlight socket, brake light power is being routed through the taillight circuit. The new part arrives next week.

[TripleKing]

OK, here is where I am. I hooked up another dual filament bulb and plugged it into the harness. As soon as I connect the ground, it kills the brown tail light circuit but the brown tail light circle will light when the brakes are applied. At no time will the brake light circuit work. when I un-ground the tail light/brake fitting, I get power through the brown wire. I don't know of this is a ground issue of a problem with the brown and white/black brake light. I have opened the harness at the rear of the bike and see nothing wrong. I have checked all grounds and all is good. No other circuits are malfunctioning.

[TripleKing]

Might be time to buy a roll of harness wrap tape (don't use electrical tape!) and start unwrapping the harness. There is a fault in there somewhere.

Krey

Okay,

When I plug in the license plate light, it shorts the system. When I plug in an accessory light I have, or I use my test light, it works normally.

When I plug in my tail light/brake light, it shorts the system. When I plug in another dual filament light, it shorts out the system. When I plug in two separate lights to the brake light, tail light harness and have a single filament light, other than the factory light, plugged into the license plate light, the entire system works fine.

Why are dual filament lights shorting my tail light/ brake light, but separate single filaments are ok. Also, I jumped ground straight to negative on the battery and it makes no difference

[ZookRick]

After fixing my over-charging problem on my 89 750, I installed a mini voltmeter. To get power to the three-wire switch, I ran the power wired to the extra connector coming out of the harness, near the right turn signal. All was well, until today, when my gauge stopped working on my way to work.


I checked all my connections at work, but still nothing. I checked the power at the connection and there was none. I also discovered that my tail light stopped working. I check fuses, but they all looked good. I swapped each one, but no joy.

I have no power to the circuit that powers the tail light. However, when I apply the brakes, both filaments of rear bulb light.

Also, I checked the lead at the front of the bike and I get power, intermittently, when have the right turn signal on, but the gauge and the tail light to not light when the turn signal is flashing.

All other lights work as they should, including headlight and gauge lights.

I am at a loss.

Edit: Went to check again. Now when I hit the brakes, I get one filament (dimly), but now my voltmeter comes on when I apply the brakes. Still no tail light. When I remove the bulb, I get no power to the voltmeter.

I am not so good at electrical but this confused me. I dont understand why a voltmeter would need more than two wires? What kind of voltmeter is it? The problem started when you hooked up the voltmeter, you should start there. I would connect it to the battery, I would want to know battery voltage especially since you were overcharging.

[TripleKing]

I am not so good at electrical but this confused me. I dont understand why a voltmeter would need more than two wires? What kind of voltmeter is it? The problem started when you hooked up the voltmeter, you should start there. I would connect it to the battery, I would want to know battery voltage especially since you were overcharging.

It is an LED voltmeter. One wire powers the LED display, one is the sensor wire and one is ground. I can run the power wire and sensor wire together. However, I want to measure voltage at the battery (sensor wire) and power from the ignition switch (running light circuit).


The gauge is not the problem Disconnecting my voltmeter completely has no effect. The problem started weeks after the voltmeter was installed.

[TripleKing]

I am not so good at electrical but this confused me. I dont understand why a voltmeter would need more than two wires? What kind of voltmeter is it? The problem started when you hooked up the voltmeter, you should start there. I would connect it to the battery, I would want to know battery voltage especially since you were overcharging.

When I at attach any dual filament setup, it craps out. When I mount a multi-functon LED strip, the electrics worth perfectly.