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Topic: Power Window Relay on 79

in Forum: C3 Electrical

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Power Window Relay on 79 (1/9)
4/16/09 10:31am

JimG

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Gloucester, VA - USA

Vette(s):
1979 T-Top, Metallic Green ZZ4 350/355 hp 405 ft/lbs torque Dual Spal Fans 700R4 4 Spd O/D Transmission 2004 Z06 Commemorative Edition

Joined: 1/29/2005
Posts: 1453

Trouble shot the window issue. Seems to be a problem with the Power Window Relay.

Here's the rub. There is no such part listed.

Anyone know if it's the same one as listed for the 78?

Jim G

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The Money Pit.... and my niece

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Power Window Relay on 79 (2/9)
4/16/09 10:59am

VetteSpecialties
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Mounds View, MN - USA

Vette(s):
70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe

Joined: 5/24/2007
Posts: 1031

I was able to find a wiring diagram for the windows circuit of an '80, and there are no relays. The full power just goes through the switches. Since we found relays for all years through '78, I would have to assume the 79-82 were all the same, with no relay.

Larry

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Power Window Relay on 79 (3/9)
4/16/09 11:52am

kstyer

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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6424

This is from a newer Vette, but it should be the same. There is no relay

Notice the system uses a reverse polarity, reversing the current through the window motors based on releasing a ground at the switch, and supplying a power to one wire, while maintaining a ground on the other wire. Until you hit a switch, all the wires from the motors are grounded.

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Power Window Relay on 79 (4/9)
4/16/09 7:37pm

JimG

So suppose I had taken out the dash and replaced it and the power booster. WHat could I have disturbed to screw this up. The Pink cable to the fuze box seems okay.

P.S. BTW, the Tach still ain't working...

P.P.S. It sounds like I'm missing a ground someplace but where could it be.
JimG2009-04-16 16:38:43

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The Money Pit.... and my niece

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Power Window Relay on 79 (5/9)
4/16/09 8:09pm

jp75vette
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Bloomfield Hills, MI - USA

Vette(s):
1975 Corvette coupe, 4 speed manual, 383 ci 9.5:1,Edelbrock dual plane Air Gap intake, Alum Heads,Comp Cam, roller Rockers, PS,PB,Tilt

Joined: 6/29/2008
Posts: 199

On the tach, do you have the filter installed and also the filter needs to be grounded.

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Power Window Relay on 79 (6/9)
4/16/09 8:11pm

JimG

Filter? All I did was unplug the big black plug in the back and replug it in when I was done. The speedo cable was easy also...

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The Money Pit.... and my niece

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Power Window Relay on 79 (7/9)
4/16/09 10:03pm

lukesvette

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HOWELL, NJ - USA

Vette(s):
1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.

Joined: 5/18/2004
Posts: 6812

On the tach, check to make sure that the plug seated correctly with the printed circuit. Also, did you ever replace the tach board?

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Power Window Relay on 79 (8/9)
4/16/09 10:08pm

kstyer

The filter is out under the hood. You may need to make sure the doors have a good ground for the windows, but check to see if you have power to the switches. A good fuse does not promise it got to the switch.

If you are not sure on the tach, you can check for power and ground to the tach, and then use a dwell meter or rpm meter on the signal wire to see if you have a signal from the dist to the dash.

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Power Window Relay on 79 (9/9)
4/16/09 10:56pm

JimG

Okay, winders is fixed...boy do I feel dumb. I was only looking from the fuzebox down to the switches. Who knew that there was a physical plug on the steering column that you could easily knock out when screwing with the dash...

Now to fix the Tach...I have not replaced the circuit board yet. I'll backtrack that wire this weekend.

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The Money Pit.... and my niece

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