Power window motors. Please help.
Thread Starter
Instructor
Joined: Jan 2007
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From: Erin NY
Power window motors. Please help.
I can't figure this out. New motors in both doors installed. Tested both motors with current and ground from battery before and after install. O.K. Checked for power from switches to both wiring harnesses before install. Both sides have power up and down. Installed motors. Motors will work for only a sec. (or not at all) and quit and only every now and then. I am quite sure that ground is O.K. because if power is applied directly from battery, motors work fine (up and down) using only a hot lead from battery and ground supplied by door sheet metal. I checked the voltage of wiring harnass at motors and believe it is full voltage. Could it be the switches? Both? Could it be the relay? I am really confused.
Any help would be greatly appreciated. Thanks.
Any help would be greatly appreciated. Thanks.
Thread Starter
Instructor
Joined: Jan 2007
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From: Erin NY
From what I have read before relay is usually under shifter console I think. I was thinking relay but can I have power to both harnesses when switches are operated (up and down) and still be bad relay. How?
Melting Slicks
Joined: May 2001
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From: May help you? You can sure as hell try!
I'm pretty sure the relay provides power to the switches IF the ignition switch is in the accessory or run position. The relay is in the front portion of the console and can be accessed by removing the shifter plate. The relay was my first thought when I read this. There is also a circuit breaker which is mounted on the firewall in the engine compartment (At least for the early C3's --I'm not sure for later ones).
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From: Inside the woods living my passion
St. Jude Donor '07-'08
I can't figure this out. New motors in both doors installed. Tested both motors with current and ground from battery before and after install. O.K. Checked for power from switches to both wiring harnesses before install. Both sides have power up and down. Installed motors. Motors will work for only a sec. (or not at all) and quit and only every now and then. I am quite sure that ground is O.K. because if power is applied directly from battery, motors work fine (up and down) using only a hot lead from battery and ground supplied by door sheet metal. I checked the voltage of wiring harnass at motors and believe it is full voltage. Could it be the switches? Both? Could it be the relay? I am really confused.
Any help would be greatly appreciated. Thanks.
Any help would be greatly appreciated. Thanks.
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Thread Starter
Instructor
Joined: Jan 2007
Posts: 109
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From: Erin NY
I'm pretty sure the relay provides power to the switches IF the ignition switch is in the accessory or run position. The relay is in the front portion of the console and can be accessed by removing the shifter plate. The relay was my first thought when I read this. There is also a circuit breaker which is mounted on the firewall in the engine compartment (At least for the early C3's --I'm not sure for later ones).
Race Director
Joined: Feb 2006
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From: Inside the woods living my passion
St. Jude Donor '07-'08
those old ones dont have a relay.
Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
Your power window motors pull a LOT of amps. It could be you have a weak connection where you can measure voltage with your volt meter (because it pulls very little amps) but when you apply a load such as your power window motor, the circuit opens because of a weak or intermittent connection. The best thing to do is to systematically jumper a hot wire directly to the motors (you've done that), then to each of the switches to see if they operate the windows properly, then to the relay, and on, until you go all the way back to the horn relay which is the main junction where the power window circuit gets its power. There really is not that many components in the power window circuit so the likely culprits as far as I can tell are, the window switches, the relay, or the circuit breaker. Also check to see that all of the connections at any connectors are free of corrosion and are making good contact.
"those old ones dont have a relay." Mine has a relay and it's a '68.
"those old ones dont have a relay." Mine has a relay and it's a '68.
Race Director
Joined: Feb 2006
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From: Inside the woods living my passion
St. Jude Donor '07-'08
Your power window motors pull a LOT of amps. It could be you have a weak connection where you can measure voltage with your volt meter (because it pulls very little amps) but when you apply a load such as your power window motor, the circuit opens because of a weak or intermittent connection. The best thing to do is to systematically jumper a hot wire directly to the motors (you've done that), then to each of the switches to see if they operate the windows properly, then to the relay, and on, until you go all the way back to the horn relay which is the main junction where the power window circuit gets its power. There really is not that many components in the power window circuit so the likely culprits as far as I can tell are, the window switches, the relay, or the circuit breaker. Also check to see that all of the connections at any connectors are free of corrosion and are making good contact.
AKA the power probe can also do so much (power& ground check )
Thread Starter
Instructor
Joined: Jan 2007
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From: Erin NY
Your power window motors pull a LOT of amps. It could be you have a weak connection where you can measure voltage with your volt meter (because it pulls very little amps) but when you apply a load such as your power window motor, the circuit opens because of a weak or intermittent connection. The best thing to do is to systematically jumper a hot wire directly to the motors (you've done that), then to each of the switches to see if they operate the windows properly, then to the relay, and on, until you go all the way back to the horn relay which is the main junction where the power window circuit gets its power. There really is not that many components in the power window circuit so the likely culprits as far as I can tell are, the window switches, the relay, or the circuit breaker. Also check to see that all of the connections at any connectors are free of corrosion and are making good contact.
Thread Starter
Instructor
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From: Erin NY
Le Mans Master
Joined: Dec 2006
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As points wear, burn, they develop resistance to current flow. There are contacts/points in the relay, and the switches.
As someone pointed out, bypassing each element until you have sucess is one way of finding your "weak link".
As someone pointed out, bypassing each element until you have sucess is one way of finding your "weak link".
Thread Starter
Instructor
Joined: Jan 2007
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From: Erin NY
Based on all else I tested it sounds like the way to go. I will test tomorrow and update.
Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
grab the wires where they go through the door opening when the door is open.......and wiggle them while depressing the power switch......sometimes the wires break inside the plastic sheating and work intermittenly..........if everything checks out ok but the window still doesnt work...look here next.....so when the window doesn't work try wiggling the wires in the open door space while depressing the switch.......if the window activates you have a broken wire
Thread Starter
Instructor
Joined: Jan 2007
Posts: 109
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From: Erin NY
grab the wires where they go through the door opening when the door is open.......and wiggle them while depressing the power switch......sometimes the wires break inside the plastic sheating and work intermittenly..........if everything checks out ok but the window still doesnt work...look here next.....so when the window doesn't work try wiggling the wires in the open door space while depressing the switch.......if the window activates you have a broken wire
Thanks.