Stumped...VC power windows and tailgate stopped working

Old Aug 6, 2017 | 05:43 PM
  #1  
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Stumped...72 VC power windows and tailgate window stopped working

Hi All,

New user here. I just a got a 72 Vista Cruiser running that has sat dormant since 1986. She is rust free and does not even smoke. All was well until yesterday when all my power windows and tailgate window just stopped working.

I consulted my 72 CSM manual and determined that the 40 Amp circuit breaker was the protection mechanism for all the electric windows so went to pull it to test but it was so hot it burnt my fingers.

I pulled it out with a screw driver and tested it and found it to be good. Next I tested the resistance of the two orn/blk wires that we connected to it by a plug. Both measured 3.2 ohms which is nearly a short.

The problem is I can not find any wiring diagrams that show any circuits related to the power windows and am stumped on how to continue trouble shooting this problem. There are two orn/blk wires connected to the circuit breaker and both seem to be shorted but I do not think that would make any sense.

I have looked through all the previous threads and can not find this same issue. Any help or guidance on this would be most appreciated.
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Last edited by ncrosetti; Aug 6, 2017 at 06:02 PM.
Old Aug 6, 2017 | 06:30 PM
  #2  
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In your CSM there should be a wiring diagram of your window circuits. I would start by disconnecting all of the switches and then jumper each individually to see which circuit is the offending one. Its hard to use an ohm meter on motor circuits because motors show up like shorts due to the coils.
Old Aug 6, 2017 | 07:03 PM
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Good idea. I will try this.

In regards to wiring diagram in CSM...nothing for pwr windows. Strange.
Old Aug 6, 2017 | 07:08 PM
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If I remember right its a separate drawing in itself.
Old Aug 6, 2017 | 09:06 PM
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Hi Eric,

I removed the connectors from both the door panels but measured nothing unusual. With that said, it is very difficult to trouble shoot without a wiring diagram. I looked through the CSM one more time and there is absolutely nothing on the power windows wirings diagram.

Also, I looked at the A-Body Wagon tail gate circuit diagram in the CSM but the wire colors do not match my car. I really wish I knew where the two Orn/Blk wires ran to so I could determine why the are shorted (or connected to a motor winding). I really can't understand why there are two of them.

If anyone else has any other wiring diagrams or experience with the VC electric window/tailgate wiring, their help would be much appreciated.
Old Aug 7, 2017 | 04:13 AM
  #6  
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I could not find anything for a 72 but I did find a 70 Chevelle maybe close enough for an idea. The orange/blk stripe is power feed.
http://photobucket.com/gallery/user/...NzQ1Mg==/?ref=
Old Aug 7, 2017 | 09:13 AM
  #7  
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The wiring for the power windows is covered in the Fisher Body Manual (Chapter 15), not the CSM. One of the unusual "features" of the power window circuit on these cars is that in addition to the breaker, there is a relay that provides power to the circuit. This is not a relay for the motor, it is an isolation relay that only applies power to the window circuit if the key is in the RUN or ACC position. This is to prevent running the high motor currents through the ignition switch. The relay is located on the driver side kick panel. If this relay is bad, you'll get no power to the window circuit.
Old Aug 7, 2017 | 08:01 PM
  #8  
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Thanks Eric and Joe!

I order a Vacuum and Wiring book that I hope has something. http://www.ebay.com/itm/332330628960

I have located a Fisher Body Manual and will buy one of these also...thanks for the tip!
http://www.ebay.com/itm/1972-Fisher-...-/371979006683
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