Bypass the bulkhead and the AMP gauge. My 71 RR had the wire burn at the bulkhead, so I cleaned the terminals and put dielectric grease on them and reinstalled. Good til one day driving smelled electric burning, thank God for the pair of lineman pliers to cut the battery cable and the fire exstinguisher. Amp gauge caught fire and burned the dash up. Kill the amp gauge and put in a more usefull volt meter under the dash.