windshield wiper motor problems in 1967 c10

[wil6775]

Hello;

I have a 1967 c10 I just started working on. The wipers won't always start when I turn the switch, even with a new switch. If I tug on the wiper they will usually start, and then run ok. When they do run, they seem slow....they also don't "park" when I turn the switch off. I know the cab was stripped and painted, so I may have a ground problem....any other ideas? Does it sound like the wiper motor itself? Here in the Pacific Northwest, wipers are very important....even in the summer!

Thanks...