Thanks redstangbob and Scumdog. I got my info from the 1965 Ford Service Manual, but maybe we are talking about the same wire in this case:
Originally Posted by whitebird
After replacing the neg. cable on the battery it starts up fine. Another problem developed -- the amp gauge on the dash is now going like crazy back & forth from D to C. & the lights are flickering including the ones on the dash. Don't know what caused this.
This will be more difficult without a lot more information.
Sounds like the ammeter is responding to a circuit breaker going on and off (but I cannot be sure without further electrical checks).
Listen intently for a clicking sound under the dash or under the hood. Let us know what you found. We had an instance where the license plate lamp holder was shorted to ground and it caused the same kind of symptoms. Check for devices going on and off, or things that just don't work. - Dave