Wiper Motor

[1968CHEVYC10]

I'm trying to troubleshoot my windshield wipers, they haven't worked as long as I've had the truck. So I'm thinking the motor's shot or the wiring is bad, I was gonna test the motor first. Do i just plug it into 12v from the battery? Or does it need some kinda fuse? I'm not much of an electrician. Thanks for the help!

[71GMC71]

I would think just using a 12 volt battery would work. Give it a try

[1968CHEVYC10]

ok thanks I'll see what happens

[rusty baker]

I just plugged mine to 12 volt and it ran. Some of them are 2 speed. So check the switch, that is what was wrong with mine.

[LockDoc]

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There is a certain sequence you have to use to test them. I will see if I can find it.

LockDoc

[LockDoc]

Here it is...

Testing the wiper motor independent of the switch:

The depressed park and non-depressed park 2-speed wiper motors can be bench tested independent of the dash switch by making the following connections:

* Ground the wiper motor housing.
* Connect a jumper wire from a +12V source to the #2 (Power) terminal on the wiper motor. It's the bottom terminal on the rectangular motor or the middle terminal on the round motor.
* Connect a jumper wire from ground to the #1 (High) terminal on the wiper motor. It's the middle terminal on the rectangular motor or the bottom terminal on the round motor. This should operate the motor at high speed.
* Leaving the above connections in place, add an additional jumper wire between the #1 (High) and #3 (Low) terminal. #3 is the top terminal on both the rectangular and round motors. This should operate the motor at low speed.
* On the rectangular case motor, leave the jumper between terminals #1 and #3 but disconnect it from ground. That should cause the motor to run (at low speed) until it reaches its park position at which point it should stop.
* On the round case motor, leave terminal #3 grounded but unhook the ground jumper from terminal #1. That should cause the motor to run (at low speed) until it reaches its park position at which point it should stop.

If the motor operates normally in the above tests but not when installed on the vehicle then the probelm is most likely in the switch or maybe the wiring. Don't forget to check the fuse. The switch can be tested with an ohmmeter.

If the motor stops immediately when switched off (doesn't return to park position), first check the motor's ground strap. Since the motor is mounted on rubber cushions, it's grounded via a copper strap attached under one of the mounting screws. This is the ground for the park switch so the parking feature won't operate if the ground strap is missing, dirty, or corroded. If the ground strap checks out okay but the motor still doesn't go into park then the problem is most likely a worn out or dirty park switch. The park switch is located inside the motor's gearbox so some disassembly is required to check/clean the switch. I recommend consulting a good repair manual for the motor disassembly procedure.

LockDoc

[1968CHEVYC10]

Originally Posted by LockDoc

Here it is...

Testing the wiper motor independent of the switch:

The depressed park and non-depressed park 2-speed wiper motors can be bench tested independent of the dash switch by making the following connections:

* Ground the wiper motor housing.
* Connect a jumper wire from a +12V source to the #2 (Power) terminal on the wiper motor. It's the bottom terminal on the rectangular motor or the middle terminal on the round motor.
* Connect a jumper wire from ground to the #1 (High) terminal on the wiper motor. It's the middle terminal on the rectangular motor or the bottom terminal on the round motor. This should operate the motor at high speed.
* Leaving the above connections in place, add an additional jumper wire between the #1 (High) and #3 (Low) terminal. #3 is the top terminal on both the rectangular and round motors. This should operate the motor at low speed.
* On the rectangular case motor, leave the jumper between terminals #1 and #3 but disconnect it from ground. That should cause the motor to run (at low speed) until it reaches its park position at which point it should stop.
* On the round case motor, leave terminal #3 grounded but unhook the ground jumper from terminal #1. That should cause the motor to run (at low speed) until it reaches its park position at which point it should stop.

If the motor operates normally in the above tests but not when installed on the vehicle then the probelm is most likely in the switch or maybe the wiring. Don't forget to check the fuse. The switch can be tested with an ohmmeter.

If the motor stops immediately when switched off (doesn't return to park position), first check the motor's ground strap. Since the motor is mounted on rubber cushions, it's grounded via a copper strap attached under one of the mounting screws. This is the ground for the park switch so the parking feature won't operate if the ground strap is missing, dirty, or corroded. If the ground strap checks out okay but the motor still doesn't go into park then the problem is most likely a worn out or dirty park switch. The park switch is located inside the motor's gearbox so some disassembly is required to check/clean the switch. I recommend consulting a good repair manual for the motor disassembly procedure.

LockDoc

Thanks locdoc that was just what I was looking for!

[Sammy]

Jeez ...Never seen that test procedure before.. talking about detailed..Kudos LOCDOC

[68 TT]

Originally Posted by Sammy

Jeez ...Never seen that test procedure before.. talking about detailed..Kudos LOCDOC

Agreed. That was great info to share. Thank you very much LockDoc.

[LockDoc]

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No problem guys I have used it many times and it works great.... I made up a couple of jumper wires with spade terminals and/or alligator clips to make it easier.

Just watch your fingers and other body parts when the arm starts rotating..

LockDoc

[gary2232]

That is good info. It should go to FAQ section.

[LockDoc]

Originally Posted by gary2232

That is good info. It should go to FAQ section.

Maybe I will make a new thread and title it "Testing Wiper Motors" so it will be easy to find in the FAQ.

LockDoc

[1968CHEVYC10]

Thanks for the info, I tested it and it works fine.

[ipoo]

I saw your other post with the custom switch, and guess that was the problem, but I had a similar problem. Mine was the original alternator was like a 34 amp and I was running MSD ignition, so basically when I updated to a 100 amp alternator the wipers started working. The stock set up in 1970 couldn't handle all the added upgrades that I made.

[PepperTreeGarage]

Wiper Motor bench test video:

https://www.youtube.com/watch?v=HYLnGaZe6zY