How to Confirm Trailer Wiring Configuration to Match 2007 Jeep Grand Cherokee  

Question:

Helpful Expert Reply:

Trailer wiring often uses a particular wire color for a particular function, such as a white wire for ground, but there is no absolute rule that this will be the case. For this reason, testing with a circuit tester like # PTW2993 is recommended. In the case of a trailer, you can use a spare battery (or your Grand Cherokee battery) to test each trailer circuit to see what light activates with the 12V input power applied.

The linked trailer wiring article illustrates the various connector types in use and the common wire color/function assignments. Again, these are typical but not universal.

A typical vehicle 4-pole harness, such as the Curt # C55381 that fits your vehicle, will use the WHITE wire for GROUND, YELLOW wire for LEFT TURN/STOP, the GREEN wire for RIGHT TURN/STOP and the BROWN wire for the RUNNING lights. If this is the type on your vehicle you can make the necessary splices on the trailer side once you confirm the function carried on each trailer wire.

If you need a new 4-pole trailer-side connector you can use Wesbar # W787264 along with Trailer Wiring Junction Box # 38656 and ring terminals # DW05702-1. Ring terminals on both the new connector leads and on the existing trailer wiring will make it a snap to make the correct connections inside the junction box. Please refer to the linked video for illustration.

You can use the circuit tester on the vehicle wires while a helper activates each function one at a time (stop, left turn, right turn and running lights). Once you confirm the function on each vehicle wire you can match these to the trailer wiring BY FUNCTION.

expert reply by: Adam R

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