Wiper motor

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Joined
Jan 29, 2011
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Location
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My Car
1971 Mustang Coupe
Never Done.
This might have been covered in the past, can not find in search of forums. Wipers not working. Checked fuse okay, wiper motor runs off the car on the bench, put in new wiper switch. Still does not work, checked my ground seems okay. Getting power too the motor at the connection plug. I just can't figure this out.

 
This might have been covered in the past, can not find in search of forums. Wipers not working. Checked fuse okay, wiper motor runs off the car on the bench, put in new wiper switch. Still does not work, checked my ground seems okay. Getting power too the motor at the connection plug. I just can't figure this out.
Try running a jumper wire from a good ground (on the engine) to the wiper motor.

 
This might have been covered in the past, can not find in search of forums. Wipers not working. Checked fuse okay, wiper motor runs off the car on the bench, put in new wiper switch. Still does not work, checked my ground seems okay. Getting power too the motor at the connection plug. I just can't figure this out.
Try running a jumper wire from a good ground (on the engine) to the wiper motor.
Yep, triple check that you've got a good ground.

 
There should be a ground strap that is part of the wiper motor assembly, top left. Sometimes the grease inside has morphed into "gum". I've repaired two by disassembly, cleaning, re-greasing, and making sure the cancel switch is adjusted properly. Chuck

F wiper shock IMG_2701.JPG

 
OK, My turn here.

I have my original motor.  It worked when I started restoration decades ago.

I have NOT checked any fuses yet, maybe that is next.

1) Neither speed works

2) I cleaned the ground strap so the through bolt makes good contact.  Nothing works

3) I disconnected the wiper transmission from the motor.  Nothing works

4) I removed the motor.  Flushed the gearbox out, relubed with red n tacky.  The gearbox spun very smoothe and free.  Reloaded the motor, Everything bolted together nicely.  Bolted it on the car to test, did not reconnect the wiper transmission.  Nothing at all.

Questions:

1) I have the arm coming off the motor toward the drivers side.  Is there a chance that it is 180 degrees off from  where it should be on the motor?  I ask because I noticed when I had the motor apart that there is a detent that rises at a point in the rotation.  I have that detent hit when the wipers are in the down position.  Is that correct.  Even if it is wrong, should the motor work anyway.

2) any chance I over torqued the arm to the motor.

3) The wire harness was getting power the other day, I assume it still is.  Should I check that again ?  I have been checking between the harness and the ground bolt on the motor mount

What Should I do now.  This is keeping me from license and cruise outings!

kcmash

 
Well, I am running ou of ideas and getting frustrated.

Tonight I check the ground just to make sure.  I ran a continuity check with my Digital Volt Meter and found continuity between the mounting bolt and the housing.  I checked the gearbox housing and the motor housing and got good continuity.  I checked the OD of the motor housing, the tip of the motor housing all with good continuity to the ground bolt.

So I figure, lets really push it and found good continuity between the motor housing and the shock tower cap bolts.  Once again solid continuity tone.  

So my next question is what can go bad with the motor?  Here are my thoughts.  

1) Not being an electrical genius, is there a chance that the circuit card in the motor just went bad, even with the solid state electronics?

2)When I took the motor apart last night to clean it all out I learned there are 2 detents on the arm drive gear that drive a plastic piston that opens a circuit.  The 2 detents are about 30 degrees apart.  I have the drive lever set to where the wipers are home when the detents are 180 degrees away on the rotation.  So when the wipers are parked the detents are on the other side of the gear.  I don't see how this would make it NOT run even a little bit.

3) 13.5 volts to one pin in the harness on High,  Another voltage to a different harness pin on low.  Tells me my switch and harness are good.

4) I should bite the bullet and buy a reproduction motor?  I cant understand what is wrong with this one.  Where do I find an OEM quality replacement?

Any help out there?

kcmash

 
The first thing I would do is to test the motor directly from the battery. Use a couple of wires and connect it directly to the car battery. If the motor runs then you know the problem is in the wiring. If it doesn't then you have a bad motor. You can look up the wiring diagram under the Mustang Data Tab - 71-73 Wikipedia.

 
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The first thing I would do is to test the motor directly from the battery. Use a couple of wires and connect it directly to the car battery.  If the motor runs then you know the problem is in the wiring.  If it doesn't then you have a bad motor. You can look up the wiring diagram under the Mustang Data Tab - 71-73 Wikipedia.
The only dumb question is the one not asked......

OK, so if I have good ground and the motor is bolted to the firewall. (Transmission disconnected)  Which of the plugs on 4 way do I apply power to?  Either of the 2 diagonal sets?  One conductor at a time?  Sorry, I cant read that schematic on the WIKI page.  I am a mechanical guy.

kcmash

 
I had problem with my motor for a while. It worked when it felt like it. Clean up the ground and replaced the bolts. Cleaned up all the connections. 

Still did not work. I picked up a used one from WCCC. They have used ones that are tested with a 90 day warranty. About the same price has a repo.

 Painted it and put it in a problem solved.

John J

https://secure.cougarpartscatalog.com/store/p/14002-Windshield-Wiper-Motor-2-Speed-Used-1971-1973-Mercury-Cougar-/-1971-1973-Ford-Mustang.html?attribs=85

 
The first thing I would do is to test the motor directly from the battery. Use a couple of wires and connect it directly to the car battery.  If the motor runs then you know the problem is in the wiring.  If it doesn't then you have a bad motor. You can look up the wiring diagram under the Mustang Data Tab - 71-73 Wikipedia.
The only dumb question is the one not asked......

OK, so if I have good ground and the motor is bolted to the firewall. (Transmission disconnected)  Which of the plugs on 4 way do I apply power to?  Either of the 2 diagonal sets?  One conductor at a time?  Sorry, I cant read that schematic on the WIKI page.  I am a mechanical guy.

kcmash
Should be either of the two sockets (females).  One is for low speed the other is high.

 
Last edited by a moderator:
Well, 

I successfully got my original motor working again.

First of all thanks to MotorCity Mustangs and my forum peers for the helpful advice.  Secondly, there is a great guy named Sam at https://www.classicwipers.com/ who shared some great advice and help.

Key Elements:

Clean the brush Contact areas

Let the springs relax fully extended overnight

Clean the ground lug to ensure good continuity between the brass and the grommet.













 
Well, 

I successfully got my original motor working again.

First of all thanks to MotorCity Mustangs and my forum peers for the helpful advice.  Secondly, there is a great guy named Sam at https://www.classicwipers.com/ who shared some great advice and help.

Key Elements:

Clean the brush Contact areas

Let the springs relax fully extended overnight

Clean the ground lug to ensure good continuity between the brass and the grommet.











Glad to see you got it working.   It amazing what a little cleaning will do.  Other than the usual wear your commutator and brushes look in great shape.  I think it will last you another 50 years.  :D

 
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