Troubleshooting Trailer Wiring that Turn Signals Cause all Lights to Flash

Published 11/17/2015

Question:

All my lights are flashing when signals are on and when I turn on truck lights breaks lock up

asked by: Travis

Expert Reply:

Sounds like your trailer connectors are miss-wired or are shorting out.

What you will first want to do is use a circuit tester like the part # 3808 to test the pins of the trailer connector on your truck for voltage in the correct places. Since I don't know what style of connector you have on your truck you will need to check out the help article I attached that has diagrams for all common trailer connectors.

If the problem is on the trailer you will need to rewire the connector of the trailer to match the diagrams as well. You can use a jumper wire on each connector pin from a vehicle battery to test the pins as well.

It sounds like the blinker circuit and the running lights are shorting out to each other and the 12 volt power circuit is shorted out to the brake output circuit.

expert reply by: Jameson C