One out, one in

[GOLDMYN]

I tried to continue but no power to anything I just had the alternator rebuilt and hooked up to new electronical voltage regular, engine started, ran perhaps 5 seconds, ammeter when to neutral , car continued to run I believe on the battery w/o charging. I shut it off and no power to anything. The alternator rebuild was single lead original. what to do now.

 

[GOLDMYN]

After searching, found the problem is a loose wire at the bulkhead connection, if I wiggle I have power. I'm afraid to take it apart, all the wires are so brittle. I could make things worse