Topic: Problems with 77 pw switch or motor?
in Forum: C3 Electrical
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I have taken most of the interior out of my 77 except the wiring. I was putting things back together and notice that my power windows no longer work (worked before). I was wondering if someone has any insight as to what may have happened or how I can test the switches to see if this is in fact the problem. Thanks to all for your help, I need it!
Matt
Matt
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Lifetime MemberYou can check for power at the pw motor using a multimeter in the voltage scale(12Volts with the switch activated. If you have no power, check the switch using a multimeter on the resistance scale. Put a red probe on one terminal and a black probe on the other terminal. With the switch closed the needle/LED readout should read at or near zero. It is also possible that a fuse is blown. Did you remove the battery terminals while working on the interior?
Scott
Scott
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Mounds View, MN - USA
Joined: 5/24/2007
Posts: 1031
Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
It is pretty unlikely that two motors, or two switches failed at the same time without being used, so it is most likely a problem of power not getting to the switches. Anything after that and it would only affect one window. That could be a fuse or a connection before the first switch.
Larry
Larry
Thanks to all for your help. I did remove the battery terminals while working on the car so I am sure that a fuse was not blown but I guess anything is possible. I will take a look at the fuse (I assume it is clearly marked on the fuse panel) and see. To Ranger3, Is it necessary that I check the pw motor located in the door? I did not take the door skins off, only the pw switches from the shifter console. What exactly do you mean by testing the "switch when it is closed"? Sorry, when it comes to electrical , get lost! Thanks for all your help!
Matthew, check the ground on the motor where it connects to the bracket. Touch (bump being careful) the motor against the medal part of the door and see if it moves. I had the same experiance with a new one for my 75. Clean the medal and bolt real good when bolting back up. Thanks
Guy
sgm2004, I have not taken the door skins off to reveal the pw motors as I wanted to stay away from having to do this if I can. I will first check the switches. Do you know if the pw fuse is located in the fuse panel under the console? Thank you!
Like Larry said, it is highly unlikely to be the motors or the switches.
You must have lost power to the switch. Check for continuity to the switches. If you don't have a diagram, Joel can send you one.
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You need to determine where you have 12 volts and where you do not. I agree that it is unlikely that both switches or motors are bad. You stated that both worked prior to working on the interior. Likely a wire is disconnected or something grounded and zapped a fuse or relay. By "switch in the closed position" I mean the the switch is held in the position that sends 12 volts of power to the pw motor.
Scott
Scott
[QUOTE=fowler12]sgm2004, I have not taken the door skins off to reveal the pw motors as I wanted to stay away from having to do this if I can. I will first check the switches. Do you know if the pw fuse is located in the fuse panel under the console? Thank you! [/QUOTE]
Matthew, yes there is a fuse on your fuse panel its labled PWR ACCY doesn't say PWR WIN like you would think. Its a 30 AMP breaker type and is silver medal instead of glass tube. I look at my GM dealer repair manual at the wiring diagram and there is a power window relay. I'm not sure where it is but I thinks it is in the console where the parking brake switch is. Because it shows the wiring coming out from under the dash. Other possiblities are that the plug ins to the switches may have came unpluged. You can check them if you pull the console. Another possiblity is that the plug ins to the window motors may have can unplugged also but again both at once is unlikely. This again would call for pulling the skins off the door. Las tyou wiring harness may have went bad. All I can think of right now if I was close to your location I would come by and try to help. Hope this does help you, good luck and take care.
GUY (AKA) sgm2004
in Forum: C3 Electrical
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