MG Car Repair: MGA 1960 Wiper motor problem?, tracer wire, wiper motor

Question
Wiper motor is coming on all by itself. Checking all wires as we speak ,but all seems well ,but I know that cant be right. Do I have to pull wipermotor out ?

Answer
Hi Ed,

First remove the black w/green tracer wire off of the wiper switch when you turn it off to see if the switch is at fault. If it still runs, most likely it is the cancel (park switch) in the gearbox of the wiper motor. (unless you have a short in the black w/green tracer wire.)

The on/off switch is a ground for the wiper motor so when you have it turned on, it grounds the black w/green tracer wire to make the motor start running. When You turn it off that ground is broken so the motor would normally stop running but that may leave the wiper arms up on the windshield so there is a park switch inside the wiper gearbox that keeps the motor running until the park switch disconnects it also.

Howard