So I'm prepping my '00 2dr 4x4 to pull my new boat. I installed a five wire flat harness (for a trailer with surge brakes, has left signal, right signal, marker lights, and reverse indicator). Anyway, I didn't check my truck's lights before wiring the harness, but tonight when I was checking the harness I noticed that the reverse indicators come on the truck (and the harness) when the brakes are pressed. The brake lights on the truck and harness also function when hitting the brakes.

I was very careful to make sure all my connections were properly isolated, and I don't really want to tear it all apart again.

Anyway, I was just wondering if there's a known common problem with this?

I'm not too concerned. Just means the surge brakes won't function. Short term, that's OK, but obviously this needs to be fixed...

 

Typical is a 4 wire harness as the brake and turn use the same wire, one left and one right. Then you have marker and backup.

 

Yeah, that's what I have. A four flat has left turn/brake, right turn/brake, marker, and ground. I wired a 5 flat (left turn/brake, right turn/brake, marker, reverse, and ground).

Either way, the reverse lights really shouldn't be coming on with the brakes. They don't come on with the turn indicator.

 

No, they should not be coming on with the brakes. Somehow something is back feeding. I'm betting it is in your wiring job.

 

No cause mine does it too!

As soon as I wired up a wiring harness, my reverse lights come on with my brake lights.

I think the truck was wired wrong to begin with.

Tell me what happens when you put on your blinkers?

 

What were the two of you using for a harness? Factory harness or splicing into the factory wiring to the tail lights? I know for a fact that my old Bravada did not do this when I installed my 7 pin connector.

 

I wired directly to the trailer wiring harness zip tied to the rear frame rail on my truck. Soldered to the 5-wire flat harness per the color coding listed in my owners manual.

As it turns out, the reverse lights only come on with my left turn signal (and brake). Everything functions normally with my right turn signal.

 

My truck had the wires just ziptied to the rear bumper, tucked up in there.

I took them down, and they were just wires, I bought a connector (see below) and spliced the wires together.


Ackwardly, when I turn my right blinker on, both reverse lights flash, but left is normal. Brake and 4 way when pressed both flash reverse lights.

 

Does it only do this when the trailer is hooked up?

 

Nope. All the time for me.