When Should My Trailer Lights Be Working

Question:

I have a 2012 Armada and tow a 34 foot travel trailer. This spring when i went to pick it up I dont have any lights on trailer when the truck ignition is off. No running lights, brake, or hazards. When I turn on the ignition, all lights function properly. Any ideas?

asked by: Mark

Expert Reply:

When the vehicle is not running and the key is in the off position, the only functions that should be working on your vehicle and trailer will be the headlights and tail lights as they are not tied into the vehicle's ignition system. If you vehicle's brake lights come on when the brake is applied, then your trailer brake lights should come on as well. It is likely the turn signals will not function while the vehicle is not running and the key is in the off position. When the vehicle is running or the key is in the accessory position, all lights and signals should be working on both the vehicle and trailer side. If this is not the case then you may have a short somewhere in your wiring harness or a blown fuse on the vehicle.

If the lights were still on while the vehicle was not running and while the key was in the off position, this would in turn drain the vehicle's battery.

expert reply by: Conner L