I'm chasing some crazy electrical gremlin on my 75 chassis. Where are all the ground points located for the dash ? I found one above the fuse panel and one ( I think ) near the radio opening. Any others ? When the key is in run position and I pull the headlight switch the wipers do a rotation This does it even with the wiper relay pulled so I think I have a ground issue. The battery ground cable is brand new. The chassis to transmission ground strap is brand new. All the headlight grounds have been cleaned and reseated. Still can't get the lights to popup and I have this funky windshield wiper issue. And when I flip on the headlight switch my temp gauge goes full hot and my voltage gauge goes full negative. Time for a exorcist .

Im not certain that the wipers are part of the headlight circuitry but it would not surprise me. There is alot of stuff going through that headlight switch.

BUT
If you have the intermitent wiper relay....its located under the hood, passenger side cowl support. That may be getting power via the headlight circuit (you said it only runs once) so look for a square relay under the hood and check your wiring.

Rich

Rich not sure if my car has intermitant wipers but it does have a relay but on the drivers side cowl support. Even with this pulled the wipers activate when the headlight switch is activated.