Ok I know its not the trailer because I've had several different trailers on the truck and when plugged into the 7 pin the battery won't charge or the lights in the trailer won't power up.

Is there a 12 volt wire I need to tap into or something to get the truck to provide power for charging the trailer battery?

Thanks

 

I may be mistaken but without the truck running it will not utalize the batteries in your truck, this is to protect them from draining. When you run down the raod it should charge your house battery on your trailer.

Have you made sure all your connections are tight? Does you converter chanrge your battery when plugged into shore power?

Hub

 

The 12v line to the trailer is hot whether the ignition is on or not. Have you checked it with a meter? Real easy to do right at the bumper plug. You may only have a blown fuse under the hood or possibly no fuse in there at all. Usually a 40a.
Bob

 

The fuse on mine is a 20a and it is located under the hood. I popped mine by accident with a short circuit.

 

Some trailers (my camper did) have a battery isolator on the incoming + side from the truck. These don't work so well. Mine died; I just wired it direct, with a 40A fuse on 8AWG wire.

HTH

Tony