Trailer Lights Not Working After Install Wiring Harness on a 2014 Kia Sorento  

Question:

Expert Reply:

To determine if the problem is with the vehicle or the trailer, first disconnect the trailer from the vehicle. Then use a circuit tester like # PTW2993 or the one that came with # C59496. Test the pins on the 4-Way using the circuit tester while someone sites in the vehicle and runs through the functions.

If all the signals are correct on the 4-Way when you test it, then the issue is on the trailer. But if the signals are not correct then there is a problem with either the wiring harness, installation, or the vehicle wiring.

The next step if the signals are not correct is to test the wires leading into the converter box. If the signals are correct going into the box from the vehicle wiring but not correct at the 4-Way that indicates a problem inside the converter and it will need to be replaced. If the signals going into the converter are not correct then there is an issue either with where the wires are connected (wrong wire, loose connection) or a problem with the vehicle wiring itself you will need to get checked out. Also make sure the converter is properly grounded to a bare metal surface.

If everything checks out correctly on the vehicle, then that indicates a problem on the trailer side. You mentioned other lights that do work. If the lights are on the outside of the trailer, they are most likely clearance lights. If your trailer has a lot of clearance lights it is possible that they are overloading the converter.

The converter in # C59496 is rated for 2.1 amps for brake and turn signals per side and 7.5 amps for running lights. Too much draw on the system should just cause the fuse to blow in # 118151. But it is also possible that it is just not allowing all the lights to come on since there is too much draw on the system.

Many trailer wiring problems are the result of dirty trailer connectors either on the vehicle, trailer, or both, and/or a bad ground connection. Make sure your trailer connectors are clean and free of corrosion. The main trailer connector and all of the lights should be grounded to clean and corrosion free bare metal surfaces. I have included a link to a video and a link to an FAQ article that should help you.

expert reply by: Michael H

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Edwin L.

6/10/2020

Hi. All the trailer lights feeding from my Kia sorento stopped working. After getting advise, we found in the boot compartment a module called: T.I.M. Towbar interface module. This one is damaged, but we cannot source such a unit? Who can help

Reply

Chris R.

6/12/2020

If it's a factory component then your best resource will be with a local Kia dealer. They should hopefully be able to provide you with this module to get the trailer connector active again.

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