To expand on Denny Graham's post. I would also check/clean all ground strap connections. If they don't exist I would add straps from transmission housing to frame, and transmission to the body. The ground strap from your battery needs to go to your transmission as that is the connection that gets the highest current drain during starting. Here's a test...run one lead from your ohmmeter to the ground post of your battery. With a piece of wire connect the other end of your ohmmeter to the place where your tail lights are grounded. If you read anymore than a few 10ths of an ohm....Bingo, you need to add straping to body panels or start cleaning bolt and screw connections on your sheetmetal.

Last edited by beltfed; 05/02/2011 2:00 PM. Reason: spelling

Six volt guy living in a twelve volt world