The grounds in the trunk are the easiest thing to ck, so start there. I left one of mine loose once, drove me crazy. Everything is controlled by a ground, and they terminate in the trunk were its nice and dry and controlled. At least on the 1st gen Neon. If they are good, then move up front. He's right about the battery cables, but since that is a newer car they should still be good. I didn't have to replace mine till around 440,000. They corrode between the individual strands and loose conductivity.