Troubleshooting Trailer Wiring, Turn Signals Work but No Stop or Running Lights

Question:

Hooking up a trailer I can get turn signals on both sides but no taillights or brake lights. If I hook up to my camper it is the same way never had this problem before.

asked by: Rex

Expert Reply:

Sounds like there is a weak ground on your trailer which is preventing the higher amperage circuits from functioning properly. First place to check is the trailer wiring connectors on both your trailer and your tow vehicle. Make sure there is no corrosion on any of the pins, especially the ground pin.

Since this happens on two trailer that means the problem is most likely the tow vehicle's wiring. Using a circuit tester like part # PTW2993 test all of the pins of your connector for voltage in the correct places like the attached video shows.

If the voltage isn't there then the problem is most likely blown trailer wiring fuses under the hood of the vehicle.

expert reply by: Jameson C