No start, just a click

[Frankenstein]

Last Saturday we drove B.A.R.T. (big ass red truck) to a few estate sales, then came home with no problems, I parked the truck on the street so I could wash my Dart in the drive way. When I was done I went to pull the truck in and wash it and it wouldn't start, all I got was a very firm "CLICK" and the dome lite went dim each time I turned the key. I replaced the starter and the starter relay (on the fender) and he fired right up, problem solved!
My wife has been driving B.A.R.T. to work and back all week with no problems until today when she called me and said the the same thing was happening in her work parking lot. Do you think I got a bad relay or could it be something else? I'm going to mess with it tonight, I just want a few ideas before I get there, it is starting to rain and I hate working on cars in parking lots.

Oh yeah, 72 F-100 with a rebuilt 390, C6, Eddy intake, Carter carb, Accell points eliminator kit with no other problems other than this.

[fordman]

bad battery or loose connections or maybe the alt isn't charging enough. it could also be dirty battery cables and or the relay could be bad.

[Frankenstein]

Just got back, it was the alternator. I'm guessing that was just starting to go out, I went to the parts store and got a new one.

[seattle67]

Hey Frankenstein,
Some of the symptoms you spoke of still lead me to believe you have a dirty or loose connection somewhere. Maybe at the battery or where the ground connects to the block, I would just clean and tighten them all, both positive and negative. Hopefully it was just the alternator, but I would hate to see a follow up post saying you or your wife got stuck somewhere.