Pinched 7-Way Trailer Wiring When Turning and Now Trailer Lights are Not Working

Question:

Hello out there! We are traveling with our RV PCSing and taking the kids to Disney before our new duty station. Long story short pinched our 7 way cord making a turn. It fried the battery and in turn now has to be replaced. It is Sat. and luckily we found an RV place for a new cord and battery, but no service in. We got the battery changed out, however Im not sure where we messed up With the wiring. I have working lights, right blinker, and the tongue jack is working, but is REVERSED. I have no brakes, brake lights or left turn signal. The truck is not reading the trailer is connected. If anyone can offer some help that would be wonderful!! Thank you

asked by: Amanda

Expert Reply:

It sounds like that the harness that connects the vehicle side trailer connector to the tow package wiring further forward on the truck is also damaged. That could be a dealer only part or we might have a replacement that can be hardwired in such as # PK11998.

You will also want to check the fuse panels for any tow package fuses that might have shorted out causing some of the functions to not work.

You will also want to use a circuit tester such as # PTW2993 to test the vehicle side connector and to test the wiring should you need to hardwire in something. I have included a picture that shows the functions of a vehicle side 7-Way. Ignore the colors and focus on the functions on each pin.

You can perform the same checks on the trailer side and also check for any loose, frayed, or otherwise damaged wires and fix as needed. As for the jack it sounds like the polarity is reversed which normally would be bad for the motor. Why yours is still "working" I am not sure unless there was a short of some kind that damaged some internal component but didn't render it non-functional.

The pinched wiring likely caused a significant short and that short could have done all sorts of things from blowing tow package fuses to disabling lights.

expert reply by: Michael H