2006 Wells Cargo Running Lights Stay on When Vehicle is Turned Off

Question:

I have a 2009 ram with factory 4 and seven pin wiring and when I shut the lights and the ignition is turned off the trailer running lights remain on. I have electric brakes with a hoppy brake controler and use the 7 pin connector. Any help would be appreciated. I have the automatic headlight on off, but even with that shut off the running lights on the trailer remain on.

asked by: john M

Expert Reply:

I have the same truck and do not have the problem you are experiencing. I do not believe it is the factory vehicle wiring that is causing the problem. It sounds like the trailer connector is mis-wired. I would use a circuit tester, item # 4PTW2993 if needed to check the connection points in the connector on the vehicle first to make sure that there is not power on the running light circuit when the vehicle and lights are turned off. If not, then the vehicle side is eliminated as the problem, and you can proceed to the trailer connector.

If the trailer connector is mis-wired, then the running lights could be attached to the power connection inside the 7-Way connector. You can use the the wiring diagram (see link) on our wiring page and check the connectors inside the trailer end and make sure each one is wired properly and not shorted between two points. The taillights, brown wire, and the 12-volt terminal, black wire, are next to each other so it is easy to make a wrong connection.

You should also check all of the ground connection points on the trailer to be sure the power is not back feeding through the ground when the vehicle is turned off and the trailer is connected. The power from the 12-volt connection could be looking for a ground and is finding the connection through the taillights. Check the taillights connections to the trailer and the ground at the trailer coupler to be sure they are connected to good clean trailer frame grounds.

expert reply by: Robert G