Wiper motor wiring

[MT65]

Finishing the under dash stuff, found my original wiper switch has only one terminal, the motor has 2....switch has 2 positions as per a two speed...checked continuity one original harness, yes one wire from switch to motor, will check other wire on motor for termination...not understanding how GM made this work...surely the switch isn’t a grounding point. Any thoughts???

[The Rocknrod]

You should have a yellow wire from the fuse panel to the motor. A light blue wire from the motor to the switch. The motor grounds thru the switch, so make sure grounds...

[clemsonteg]

I've been using this http://67-72chevytrucks.com/vboard/s...19&postcount=4 and the American Autowire diagram https://www.americanautowire.com/med...20IN%200.0.pdf

[MT65]

Originally Posted by The Rocknrod

You should have a yellow wire from the fuse panel to the motor. A light blue wire from the motor to the switch. The motor grounds thru the switch, so make sure grounds...

Yes, checked that this morning, never had a wiper switch be the ground in the past, knowing that it was marginal when I drove home in a snow storm through most of eastern Oregon, I just ordered one of Newport Enginnering new ones. Do not want any issues in the future, and one more speed can’t hurt.
I had luckily kept the old harness and panel to check items like this, thanks for the help tho......

[MT65]

Originally Posted by clemsonteg

I've been using this http://67-72chevytrucks.com/vboard/s...19&postcount=4 and the American Autowire diagram https://www.americanautowire.com/med...20IN%200.0.pdf

My switch only has one terminal, I think it has been fooled with in the past, new parts due in Thursday....

[nsb29]

The reason that it uses a ground is when you turn the switch off there still has to be power to the motor so it can park With the 2 speed switch and motor you basically have two grounds one ground to Low speed the other one for high-speed

[The Rocknrod]

Originally Posted by MT65

Yes, checked that this morning, never had a wiper switch be the ground in the past, knowing that it was marginal when I drove home in a snow storm through most of eastern Oregon, I just ordered one of Newport Enginnering new ones. Do not want any issues in the future, and one more speed can’t hurt.
I had luckily kept the old harness and panel to check items like this, thanks for the help tho......

On an OEM motor the wiper switch IS the ground. The yellow is power, the motor grounds THRU the switch. - https://67-72chevytrucks.com/vboard/...d.php?t=695112
When the wiper switch is turned on, it completes the circuit to ground (the dash). - http://67-72chevytrucks.com/vboard/s...d.php?t=413551