Blinkers and Brake Lights Quit Working When Headlights are Turned on in 1999 Jeep Cherokee

Question:

Hi, I just bought one of your trailer light wiring kits for my 99 Jeep Cherokee and its helped solve 1 problem, but I now have a weird issue I cant figure out. All of my lights function, just not all together. If my tail lights arent on, my brake lights and blinkers work as they should. When I kick my tail lights on my blinkers and brake lights wont work anymore. I can turn the tail lights off and the the blinkers/brakes wont come back on until I unplug the trailer from the harness on the back of the vehicle and then plug it back in. When I unplug them and give them a second, then plug them back in everything works. So as it is now I have to choose between tail lights, or brake/blinkers. Any pointers would be great.

asked by: Brandon B

Expert Reply:

It sounds like you have a bad ground or a short in your wiring somewhere. Another possibility is if you have a lot of lights on your trailer it could be causing the lights to overdraw.

To find out what end the problem is on you will need to use a Circuit Tester # PTW2993 to test the different functions on the connector of your 1999 Jeep Cherokee. For your trailer side you will just need to use a different 12V source of power like the battery in your Jeep. Check to see if each function works as it should.

Whether the problem seems to be on your Jeep or your trailer you will want to start off by checking that all of the ground connections are solid and connected to a clean, bare metal surface. If they look good then you will want to check your wiring for any places that are corroded, bent, have exposed wiring, or look damaged. You will want to replace any wiring that looks like this as it would be causing the short.

I have also attached a few wiring articles for you to check out as well.

expert reply by: Jon G