Electrical glitch after taillight replacement

[Navaho6]

I replace the stock taillight with a Baja Designs LED taillight last night. the stock assembly has two wires going to a bulb that illuminates the licence plate. The new taillight does not have this separate light so I just left these two wires unplugged.

Two problems occurred:

1st problem - The new taillight has no brake function. Nothing changes when I hit the brake. Wiring is black to black, blue to blue and red to yellow. I swapped the yellow and blue wires. Still not working properly.

2nd problem - battery went dead today during a ride. This is a new bike with 1200 miles. Battery has always been strong. Would those two disconnected wires have anything to do with the battery going dead?

 

[K7MDL]

The lic plate wires should have been insulated when you disconnected them to prevent shorting by contact during vibration (including intermittant contact). If the hot wire (the other is ground) contacts the frame or a ground wire, then it will blow a fuse, maybe burn the wire, or drain your battery when the key is on (intermittants can cause problems without blowing a fuse). These are unlikely though.

You need to go back to your wiring and identify which is the lamp ground wire. You should be able to trace it to the bulb socket and see it contacts the bulb base metal socket. You should be able to trace the brake and running light wires also to the bulb contacts. Measure your bike-side voltages (all disconnected) with the key on and see which has 12V, and which has 12V only with brake on, and one (ground) should be 0V always.

As far as the battery, I do not believe in coincidence that much. If the battery went dead just after a wiring change, I would suspect the wiring is not right. With key off, measure your battery voltage. Measure it again with the key on. Should not change that much. Might have to charge your battery first. A better test is to measure the current draw of the battery, but you may not have that equipment or experience.

I woud start with your tail light wiring, make sure it is right. Measuring the voltages, the colors are unimportant.

 

[Navaho6]

Thanks for the advice. I checked the wiring on the tail light. Red to blue, blue to blue. The light works either way but with no brake function. Confusing. I'll have to get a good multi-tester and check everything out next w/e.

I found a large blue wire that was damaged - got smashed between the battery and subframe. The insulation was rubbed off on one side (against the battery) and several wire strands broken. This wire goes from the Neg terminal on the battery to the voltage regulator. It doesn't show up on the wiring diagram in the owners manual.

 

[K7MDL]

The '08 onwards have that blue neg. wire. Added with the FI I believe. Since it is on the ground side, not likely a cause of battery drain though. Your bike may cease to run if it breaks though.

If you do not have a decent voltmeter handy, a 12V light bulb may suffice. Even your tail light, just validate with your eyes you have the base of the bulb and one of the filament wires and clip the base to a bare metal spot on the chassis or engine block, and the other side connect to each wire in question. You can remove the taillight reflector easily and move anywhere around the bike, makes for a reasonable trailside voltmeter which can be handy in the middle of nowhere. Practice with it in the garage.

- McGyver

 

[Navaho6]

I put the battery on a 1 amp and 2 amp charge last night. Withing a few seconds, it showed full charge. Battery was not dead. I'm guessing the ground wire or some other wire damage is the culprit. I just can't figure out how to pull the blue wire connector out of the harness. I wonder if I can just repair the damage with a wire connector.

 

[glangston]

I saved this from another thread...for installing the Baja type rear light that came with the powerup kit.

If using the rear light that came with the power up kit it goes like this,,,,or this is what you'll need to get it all wired up. On the connector on the bike the wires go like this.....the red with the black stripe is the + for the right turn signal..... there is no black wire.... the blue wire is the ground for all the lights including the turn signals.....the lite blue is the + for the left turn signal....the yellow wire is for the running lights....and the green wire is for the brake light....


Now for the light itself......the red wire is the brake light.....the black is the ground..... and the yellow is the running light..........this info is from an 08 TE450.

 

[K7MDL]

I put the battery on a 1 amp and 2 amp charge last night. Withing a few seconds, it showed full charge. Battery was not dead. I'm guessing the ground wire or some other wire damage is the culprit. I just can't figure out how to pull the blue wire connector out of the harness. I wonder if I can just repair the damage with a wire connector.

That does not look like any (or at least very few) wires are broken. I would just tape it up.

To get the connector out of the shell, you can take an awl or jewelers flat blade screwdriver and press the tangs in on the side of the pin. If you have never seen a pin outside of the shell, it is hard to visualize where to press.

Even if the wire was damaged, you can just cut the damaged section out and splice with a crimped butt splice connector.

- Mike

 

[Navaho6]

Problems solved.

The electrical power issue was a defective oem battery. The charger showed full charge but I checked the voltage after a 5 minute rest. Only 11 volts.

I suspected the battery all along so I ordered a 5.0ah Turn-tech last week. Turn-tech = 7 lb weight savings!!!

The tail light works perfectly when wired up correctly . Blue wire from bike goes to the red wire on the tail light.