Replacing tail light assembly

I thought I was doing the simplest job ever in replacing a tail light assembly that I ordered from the factory. My old lights were ok, but the liscense plate mounting bracket broke, so the left tail light assembly had the be replaced.

I disconnected the wires one at time and connected them to the new assembly. Three wires coming out of back of camper: Red, yellow, green. Three wires on tail light: black, green, red. I reconnected green to green, yellow to red on tail light, and red to black on tail light. Now, nothing works except the running lights (appear to be tied into green wire) and the parking light (bottom light in fixture) on the right tail light assembly. No turn signals, brake ligihts, or back up lights on either side, and not even a tail light on in the new left fixture. Really? Are you kidding me?

The only clue that I have been able to gleen from the wiring diagram in my manual is a comment about the fixture being "grounded to exterior skin". My new fixture came with a couple of short lengths of white wire that where connected to the back side (the side that would be against the exterior of the TM when the fixture was screwed back on). On the original fixture, these wires were both clipped off, so I did the same thing to mine. All of my testing was with the fixture hanging loose, and therefore no contact between the clipped wires and the exterior skin. Could this be causing my problem? This seems like a ridiculous way to ground the whole assembly.

It is night time here, so I can't check until tomorrow. I am really not very hopeful that this is the problem.

Any thoughts from any of the electrical gurus out there would be appreciated.

[MudDog]

I'm betting it is a ground problem.

On the original fixture there is one hot wire going to each bulb and the bulbs are attached to metal brackets...and the metal brackets have a metal screw that passes thru the plastic housing to the metal skin of the TM.

That screw is grounding the bulb and if it is not making good metal on metal contact you'll have no ground and no lights.

Take a short piece of wire and touch one end to the metal bracket holding the bulb and the other end to the TM skin and see if the light comes on...if it does, a bad ground connection is your problem. If you have a bad ground, make sure the screw doesn't have calk or something on it preventing a good connection, or run a short ground wire from the bracket around or thru the plastic housing to the skin behind the plastic housing.

I was doing all my testing yesterday with the fixture hanging, but not attached. As soon as I attached it this morning, the tail lights, brake lights, and turn signals all starting working as they should. However, my back up lights still are not working on either side. I have the yellow wire out of the camper connected to the red wire on the fixture that runs to the top bulb. My ground screw is in place. No lights when TV is in reverse (TV backup lights are on).

70 degrees here yesterday, today it is snowing. Life in the upper midwest, gotta love it.

Any other thoughts out there?

[MudDog]

Forgive what may be a silly question, but did the back-up lights work before?

A lot of times the middle pin on the 7 pin connector on the tow vehicle is not wired for backup lights.

On my first tow vehicle, the dealer didn't wire the middle pin when they installed the hitch. I ended up wiring it later myself by tapping into the backup wire on the tow vehicle and running it to the middle pin on the 7 pin receptacle.

On my current tow vehicle (Tacoma with factory tow package), some on the Toyota forums have said it is wired, oither have said it is not. I have a feeling it is not on my truck, as my backup lights no longer work.

If you have a multi-meter or a 7 pin test plug, check the backup pin at the tow vehicle to make sure it is wired.

[4Kids2Dogs]

Same thing happened to us. The backup lights were not wired on our truck. DH had to wire it himself.