I have a late 60's model Ford pickup, F-100 with V8 engine. Don't use it but about once a week. Three weeks ago it wouldn't start. Old battery was way down, so I tried charging it and it wouldn't build up. Put on new battery and it started right up and I thought the problem was solved.
Week later it started up just fine and I went to the bank. Tried to start it back up as it rolled backward. Something I seldom do. Motor turned over fine;but wouldn't start. Stopped the vehicle completely and tried again and nothing. Got out,raised the hood and put a screwdriver between the battery post and to the starter post on the starter relay. Just heard a buzzing sound. (I'm real hard of hearing;but wear a hearing aid.) So couldn't tell where the buzzing sound was coming from? Figure it was the starter;but can the starter relay make a buzzing sound too when you jump across the battery post side to the starter post?
Then got back in the truck and tried it again and the truck started right up. So wondering now if the started relay could be good and the starter itself just bad enough to not work part of the time? Before this I had always thought that when the starter went bad,it went bad completely. Am I wrong on that?