best thing to start with is under the hood... see if you have power at the alternator with the battery hooked up.... should be some on the back stud.... next follow the wires, you should have a fusible link inline from the alternator to the battery I believe, if all that checks out, move on the inside at the fuse box, with a test light see if you have power coming on on the top left terminal thats your main power, if you dont have power there, then its most likely the connection between the fuse panel and underhood wiring on the firewall, unscrew the two apart, and clean the connections...