76 Window Motor Issues
Thread Starter
Instructor
Joined: Jul 2013
Posts: 119
Likes: 2
From: San Francisco California
76 Window Motor Issues
The passenger side window motor seemed to have gone bad as it would not go up or down anymore (original window motor). So I bought a new one from Ecklers and connected it and it did not work. I have a couple basic questions from someone not as electrically inclined:
1. Both motors have resistance when connected to volt meter outside of car.
2. Both motors don't turn when directly connected to 12v power. Shouldn't the motor run in either direction when connected directly to 12v power as any DC motor would or does it need to be switched?
3. The driver side motor works. I disconnected the motor on the driver side and then connected the driver side wiring to the passenger side old motor and the new motor, but both still do not turn. With good power on the driver side and working switch shouldn't the right side motor work when connected and switched up / down?
Driving me crazy......
Thanks for your input!
1. Both motors have resistance when connected to volt meter outside of car.
2. Both motors don't turn when directly connected to 12v power. Shouldn't the motor run in either direction when connected directly to 12v power as any DC motor would or does it need to be switched?
3. The driver side motor works. I disconnected the motor on the driver side and then connected the driver side wiring to the passenger side old motor and the new motor, but both still do not turn. With good power on the driver side and working switch shouldn't the right side motor work when connected and switched up / down?
Driving me crazy......
Thanks for your input!
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,005
Likes: 4,161
From: US-PNW
More sleuthing is needed. You may have a bad original motor; and you may have a bad Ecklers motor.
The only other things to try are:
The only other things to try are:
- Does the driver motor work on the passenger wiring?
- Does the driver motor work with the direct 12v power (the way you'd expect)?
- Does the driver motor yield the same resistance as the other two?
Thread Starter
Instructor
Joined: Jul 2013
Posts: 119
Likes: 2
From: San Francisco California
Thank you for the input. I'll try to connect the driver motor to the passenger side switch to see if that works. Maybe I'm just in denial that the new motor does not actually work. Bummer. If the new tests reveal this then I'll reach out to Ecklers for the return or replacement.
Thanks
Thanks
Melting Slicks
Joined: Jul 2010
Posts: 3,176
Likes: 633
From: perth western australia
don't want to be a captain obvious here , but you know both inputs to the motors are positive . the earth is the motor bolted to the door and the earth goes through the hinge back into the birdcage .
Thread Starter
Instructor
Joined: Jul 2013
Posts: 119
Likes: 2
From: San Francisco California
I thought that might be true so how do I test the window motor unit outside of the car with a 12v battery? Where does the negative terminal on the batter go to on the unit?
Thread Starter
Instructor
Joined: Jul 2013
Posts: 119
Likes: 2
From: San Francisco California
Bazza77 - You just SOLVED IT! I cannot believe it. so I was connecting the motor outside the door panel and leaving it on the seat. When I switched it up or down it did not function. Once I touched the gear box to door panel metal frame it now Operated. Sometimes the simple things just boggle the mind.
Thank You. You are a genius and I apparently am not!
Thank You. You are a genius and I apparently am not!
Melting Slicks
Joined: Jul 2010
Posts: 3,176
Likes: 633
From: perth western australia
So the new motor is OK and the original is bad ?
You can add a ground wire on one of the three screws that hold the motor on the regulator , just make sure it doesn't get caught up in the movement , and run that through the door and into you birdcage up under the dash for a better ground if it helps.
You can add a ground wire on one of the three screws that hold the motor on the regulator , just make sure it doesn't get caught up in the movement , and run that through the door and into you birdcage up under the dash for a better ground if it helps.
Thread Starter
Instructor
Joined: Jul 2013
Posts: 119
Likes: 2
From: San Francisco California
So the new motor is OK and the original is bad ?
You can add a ground wire on one of the three screws that hold the motor on the regulator , just make sure it doesn't get caught up in the movement , and run that through the door and into you birdcage up under the dash for a better ground if it helps.
You can add a ground wire on one of the three screws that hold the motor on the regulator , just make sure it doesn't get caught up in the movement , and run that through the door and into you birdcage up under the dash for a better ground if it helps.
New motor is good. Old motor is bad. Now to find some visual documents how to re-install the motor after taking it out. The Build Sheets are not clear and the Haynes manual either. Any diagrams how this is done. Glass is still in the door panel and all brackets.
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Melting Slicks
Joined: Jul 2010
Posts: 3,176
Likes: 633
From: perth western australia
here's a step by step of a conversion from manual to electric , might be a help to you
https://tech.corvettecentral.com/201...ic-windows-c3/
https://tech.corvettecentral.com/201...ic-windows-c3/
Melting Slicks
Joined: May 2015
Posts: 2,365
Likes: 428
From: Cape Girardeau Missouri
Glad you got it fixed!
I should have written the first time I read that the power window motors are case grounded with the electrical connectors to +12V (up/down). I know it seems strange (at first) for a DC motor where you normally just flip the positive and negative connections to reverse but there are a couple excellent reasons it's done this way in a car:
1) A simple single-pole double-throw switch is used that contains only +12V so there's zero chance of the switch shorting internally. No need for the double-pole double throw "reversing" switch.
2) It reduces the amount of wiring because there's no need to run -12V to the switches.
I should have written the first time I read that the power window motors are case grounded with the electrical connectors to +12V (up/down). I know it seems strange (at first) for a DC motor where you normally just flip the positive and negative connections to reverse but there are a couple excellent reasons it's done this way in a car:
1) A simple single-pole double-throw switch is used that contains only +12V so there's zero chance of the switch shorting internally. No need for the double-pole double throw "reversing" switch.
2) It reduces the amount of wiring because there's no need to run -12V to the switches.