Thanks all for the replies. Sorry for the delay, I’ve just seen them! Kind of lost track of the thread but found it today. I don’t think it’s a vacuum set up. The motor is strong and the wipers work well on either speed. If I rock the switch back and forth I can get the switch to contact the off position. I’m worried that contact position will fail eventually. It’s hard to get my head under there without taking out the radio, which I’m trying to avoid. (Why anyone one would cut a dash is beyond me). I can feel with my hand there is a switch component directly behind the knob with a steel cable jacket coming off it. The cable goes somewhere off in the direction of the wiper arms mechanism so I am assuming the motor is mounted directly behind the dash switch. Doesn’t seem very big. I’ll start searching the manual, thanks Bill, but if anyone can use my description to come up with any other ideas, I’d greatly sppreciate it.
