GoingForBroke

I just bought a fairly light travel trailer to hook to my Cherokee. It has the 7 pin trailer plug do to having brakes, and I want to utilize them.

I bought the brake light and turn signal harness, but it is obviously a 4 pin adapter. In the brake light wiring panel, there is a blue wire meant for electric trailer brakes. I also just ordered this:


I guess I'll just splice the blue wire together instead of using the OEM plug that comes with it? That wire runs to the kick panel for a controller.

Here's my main question. There is a yellow wire (backup lights?) and a black wire (power). I don't know where to run them... Has anyone done this?

Basslicks

Here's a diagram of the 7-pin:



The "auxillary" in the above diagram is for reverse lights according to etrailer.com

The yellow one you're asking about is for Left Hand turn signal.

The blue wire needs to be run to a brake controller otherwise, as soon as power is applied to it, the brakes will be on full power. This can cause a plethora of problems.

The black one needs to go to 12 volt constant power - best thing to do there is run it to a relay or at least a fused feed off the fuse block under the engine bay. I used to run stuff like that off the battery, but it's not a great idea.

Ground your white wire to the nearest BARE METAL surface that isn't isolated from the uniframe by an insulator. You can just find a spot on the bumper bracket or bumper itself, drill a hole, sand away the paint around it, and bolt a bolt in that spot to hold it in place.

As far as the turn signal wires and the tail light wires, you can just splice those into the respective wires on your taillight harnesses.

I've never done a 7-pin, but I have done a 6-pin. Only difference is the addition of the reverse lighting.

Just as a suggestion - whatever you splice, be sure to cover in dielectric grease and then heat-shrink over it. Electrical tape is good, but tends to unravel with heat and it's not as water-resistant as heat shrink. If you know how to solder, definitely do that, but it's not necessary as long as you secure the wires together correctly. - Dielectric grease will help protect the connection from corrosion and water, as well as ensure a better connection.

Hope all this helps!