My442

Over the past month, the wipers on my 70 442 would go on while driving, and the switch is off.
The only way to stop them is to open the hood and jiggle the connector to the wiper motor.
I think the motor has a short curcuit......any ideas????

Lady72nRob71

Sounds like you are very close to the problem; just have to evict the ghost...
Not sure if the motor units can be easily disassembled and checked out, but that is where I would start.

joe_padavano

The problem is that the wiper motors on these cars use what's called a shunt winding. There is a high speed motor winding that (surprise!) is used for the high speed. There is a separate shunt winding that is wound backwards. For low speed, both the high speed and shunt windings are energized, and the shunt partially cancels the high speed winding, to provide the low speed. When you turn the wipers off, the high speed winding is disconnected but the shunt winding stays energized until the arms are in the park position, at which point a cam in the motor opens the park terminals. What's happening in your case is that the park terminals aren't opening, thus the haunted wipers. This can be caused by a bad motor, bad switch, or bad wiring in between.

BlackGold

The chassis service manual has some good diagrams and diagnosis charts which show in detail what Joe's talking about. Like he said, the contacts on the park switch are probably not opening, though there could be several reasons.

The other possibility is that one of the wires from your dash switch (or the switch itself) is intermittently shorting to ground. Since the wiper motor always completes a cycle once started, all it would take is a brief short to ground to start a cycle. ad infineum.