Troubleshooting Trailer Lights Not Working After Crackling Sound When Connecting to Tow Vehicle

Question:

All of my trailer lights were working. I went to plug the trailer plug into the truck outlet while the truck was running and I heard a crackling sound I think I blew a fuse. But I cannot find a blown fuse. I checked all the lights on the trailer separately and they all work and the running lights. Please help

asked by: Joe W

Helpful Expert Reply:

I am not sure what might have caused the crackling sound when hooking up your trailer to your tow vehicle.

It might indicate a blown fuse, as you mentioned, but that would still be an odd sound. Either way, if you haven't already, check your vehicle's owner's manual for the fuse locations pertaining to trailer lights to make sure they are all in good working order. Otherwise, I'm wondering if the crackling noise wasn't a result of some moisure that might have been caught inside the pins on the connector, and maybe when connected to the running vehicle it caused some kind of short to occur.

I recommend using a circuit tester like # PTW2993 to test the pins on your vehicle side connector. Have a buddy run through the functions inside the vehicle and test the corresponding pins for power. If you are not receiving power, there is an issue somewhere on the vehicle side harness and wiring. Check the wiring on the vehicle for any damaged or exposed areas. If you have an aftermarket 4-Way converter box installed for trailer wiring on the vehicle, it may have shorted out. I have attached a video that demonstrates how to test this.

If you are not able to resolve the issue, please let me know and I will be happy to help you further.

expert reply by: Chris R