Wiring Harness for a 2007 Kia Sorento

Expert Reply:

The Tow Package Wiring Harness with 4 Pole Trailer Connector, part # 118250 will work with your vehicle, if it is equipped with the factory tow package. This harness has two connectors on it, one uses the existing factory installed harness to obtain 12 volt power from the battery, the other connector provides the lighting signals.

If your vehicle does not have the tow package, you will need to use the Upgraded Circuit Protected Modulite, part # 119176KIT. This connector would need to be hardwired into the existing wiring, using the supplied circuit tester to locate the correct circuits to tap into.

To troubleshoot your current harness, you will want to first determine if the wiring problem is with the vehicle itself or the trailer. Use a circuit tester, such as part # 40376 on the trailer connector, as each function is activated. If the connector checks out okay, the problem exists with the wiring on the trailer. You will have to trace each circuit back from the connector, looking for broken or pinched wires. Closely examine the insulation on the wires, looking for worn spots or cracks which would allow the copper conductor to come into contact with the trailer frame or other metal parts.
If the trailer connector on the vehicle does not show current on the left turn pin or the running light pin, troubleshoot the converter. Trace the wires back from the connector on the vehicle, looking for the converter box. Test the wires for the left turn (yellow wire) and the taillight (brown wire) on the input side of the box as each function is activated. If you have a signal going into the box, but not exiting on the other side, the converter has shorted out and must be replaced.

If you determine that the converter needs to be replaced, you will want to examine that trailer wiring as described above. If you replace the converter without repairing the problem that caused the converter to short out, you will damage the new one.

expert reply by: Mike L