[Brian R.]

It is difficult to connect a battery backward. The cables are usually so stiff and only long as they need to be. Have the dealer who sold you the truck to come and replace that device or pay it off and get them to remove it. Until you know its status, it is difficult to troubleshoot. I have not seen this behavior previously without having either blown a fuse or fried a wire(s). Look under the dash for blackend wires or connections.