Trailer Running Lights Do Not Work for Trailer Towed by 2012 Kia Sorento

Question:

I have a 2012 kia Sorento which I hooked up the harness made for a vehicle which comes with a towing package hookup under vehicle. All lighs used to function properly on SUV and trailer but now the running lights nights lights on the trailer no longer work. Using a connection tester plugged into the back of the SUV the problem is at the SUV and not the trailer. The tester shows the stop ligths, signal , brake workig properly but nothing when the night lights are on. Is the switch box shot? The checked all connections are all tight... How can I find out if the box needs to be replaced? Its a year old... Or better yet how do I get the night ligths operating again?

asked by: Dan

Helpful Expert Reply:

If the 4-Way does not show power for the running lights then it could be the converter or it could be something with the vehicle. Consult the vehicle owners manual first to find the locations of the tow package wiring fuses or relays and check the ones related to the running lights. If blown, you should just have to replace with a new one and everything will work again.

If everything is intact you will want to use your tester to test the wires going into the converter from the vehicle. If they show power but the output dies not then the converter is bad and will need to be replaced.

If the converter went bad because of a short on a trailer then you will need to track down and fix the short first or this will keep happening. Make sure the trailer connectors are clean and free of corrosion. Make sure that the main trailer connector ground and the grounds for all the lights are attached to clean and corrosion free bare metal surfaces.

Check for frayed wires and make any repairs to the trailer wiring as needed. I have included a link to an FAQ article and video that should help you.

expert reply by: Michael H