Trailer Running Lights Do Not Work with Trailer Connected to 2012 Dodge Grand Caravan

Question:

My vehicle is equipped with factory towing package containing a large round 4 connector plug for the vehicle connected with small 4 flat plug at the other end which connects to the utility trailer. Issue: running lights, side marker lights not working however stop and signal lights no issues and bright. Have power on the brown wire at rear of the vehicle and power extends back to the trailer lights but fails to activate the lights. When connected to another vehicle no issues with this setup. vehicle 2012 Dodge Grand Caravan Crew factory wiring harness and hitch. Please pass along any thoughts you may have with this situation.

asked by: Don L

Expert Reply:

The way you are describing the trailer connectors on the vehicle it does not sound like a factory connector. But regardless of if it is factory or aftermarket, check to make sure there is not a loose white ground wire not connected to anything. The harness will not function fully without a proper ground.

It is possible that the lights on the trailer are over drawing the ability of the trailer wiring on the 2012 Dodge Grand Caravan. If it is factory wiring then you would need to consult the owners manual or a Dodge tech to determine what the capacity is. Then you would need to know how much the running light circuits draw on the trailer.

It could also be that the trailer does have a weak ground that the Caravan harness cannot overcome yet it does still work on other vehicles. You will need to make sure that the grounds for the main trailer connector and all of the lights are attached to clean and corrosion free bare metal surfaces.

If the trailer has an aluminum frame, tilt bed, or folding tongue running jumper grounds from the lights to the main trailer connector ground might help. Make sure that the vehicle and trailer side connectors are clean and free of corrosion.

expert reply by: Michael H