Troubleshooting Interior Trailer Lights not Working when Connected to 2109 Ford F150

Question:

Hi, I am at a loss and was told that you guys might know the answer to this. I have a 2019 ford f150 xlt with a tow package and a 2019 adams julite horse trailer. When I hook the trailer up, my truck tells me that the trailer is connected and all the outside lights on the trailer come on. However, when I tried to turn the load lights and the interior lights on in the trailer it doesnt work. the truck is brand new, the trailer is brand new, everything else works perfectly. Im told that this is a problem with ford because of the intelligent trailer connection. I have read in some forums that there is a pattern or sequence you can go through when you turn the vehicle on that will cause the lights in the interior to come on. Have you heard of this before and if so could you tell me how to turn these lights on? Thank you very much for your time

asked by: Robin E

Expert Reply:

Interior lights are powered by the 12V circuit from your tow package's 7-way.

Newer Fords like the 2019 F150 need to have the trailer hooked up to the 7-way first. Then, you need to press on the brake pedal for the circuit to become active. This should get everything working.

If it doesn't, then open your hood and check the 12V fuse in the circuit box. If that is blown, you will need to replace it.

If the fuse looks okay and you are still unable to get your lights working, then use a 7-way tester like part # 6562 to ensure all functions are working properly. If the 12V is not, you may need to take it to your local dealership to get it serviced. I've linked to a video review of this tester below.

expert reply by: Kef G