71 wiper problem (electrical)

[Mike Rajchel]

I am having trouble getting the wipers to operate. I believe the vacuum part of the system is good. The fuse is good and the door open switch is being made. I have replaced the motor with no luck. Yesterday the motor became very hot while trouble shooting. I am not sure what position the park switch under the dash should be in. The switch on the console seems to be good.

Is there an easy to read trouble shooting guide or reference for the electrical part of this system?

Does anyone have any ideas as to where I should begin?

Any and all help is very much appreciated.

Regards,
Mike

[Jack H.]

Re: 71 wiper problem (electrical)

A complete tutorial on how the wiper motor relates to the wiper door system is provided in your copy of the 1971 Chevrolet Chassis Service Manual. Basically, the vac system gets the wiper door opened up contacting a micro-switch mounted to the engine compartment firewall, closing the switch.

Power to the wiper motor runs from the fuse block, through the cut-off switch below the steering column (switch serves to halt the wiper motor to enable you to change wiper blades) and on to the wiper door micro switch. When the micro switch is closed, power simply flows through it to the wiper motor completing the circuit.

What can go wrong?

(1) Service switch below the steering column is left in the service (OFF) position.

(2) Adjustment of the micro switch on the wiper door is improper causing the switch not to close when the door is open OR the micro switch is faulty.

(3) Interconnect wires in the engine compartment are faulty, not making proper contact at their respective plug recepticals (pull and clean the contacts).

(4) Wiper motor's discrete ground wire is faulty causing the motor power circuit not to be complete.

(5) The wiper motor is worn out and needs rebuilding.