We have a 1974 Corvette Stingray with 26,000 original miles. The drivers door electric window stopped working and I am trying to figure out what to replace, and I need you're help in locating a relay on the firewall that has a red and orange wire that according to you're 1968 to 1977 corvette power window wiring schematic shows a relay on the firewall in the upper left hand corner of this schematic. I have tried numerous auto parts places here in Saint Marys, GA and no one seems to know what it is or what it does. If you can look up this schematic and tell me if this could be the problem why the electric window doesn't work, I can order the part from you. I have checked the switch on the console and it seems to be in good working condition, the right window works fine. I put a test light on this relay and according to your schematic instructions only the red wire should be on with the ignition switch. When I checked this relay with a test light and the ignition off, both terminals lite up and have power on both wires. Does this mean that the relay has blown? We also checked all the fuses, and are unable to find the problem. Need your help.

 

I would not think it is the relay. It appears common for both doors and you say one is working. Power to both doors come off on pink wire from relay. I would check the motor for the window not working and first the ground as they usually cause problems. If you take a test light you can check at motor if it is making it there and work back

 

After checking all the other things check the wires between the door and the body for a broken wire. Ask me how I know???

 

Switches too are prone to failure. Do you hear any clicking when you cycle the switch, does the window try to move up or down?

 

the right window works fine no clicking from either window thanks for responding

 

I don't recall any relay involving the power windows on my '72, and I installed them myself, sometime back in '95 or so....it was a manual window car....the switches are known to fail, and so to take them apart and clean/burnish the contacts and CAREFULLY put them together again.....

 

I have found the replacement switches to be prone to failure as well.... to the point that I keep a replacement in the car.

 

Me too, they are junk, I wonder where they were made?

 

 

Watch the switch rebuild video we have on Youtube. The original switches are easy to rebuild, the aftermarket... they are harder to re-crimp but when there is a failure it's usually due to the fact that the contacts inside the switch don't have enough tension on them... when you get the bottom loose from the switch you can put more tension on the contacts and this usually corrects the issue.

I've not had any issues with the current supplier we use for the aftermarket switches, but I have had issues with others in the past.

Willcox

 

Great troubleshooting steps, found my fairly new relay was working sometimes and then not at others, works about 5 minutes then stops, later I go back out and it works, definatly in the relay.

I was wondering if I could use a newer style relay in its place, I have several laying around from electric fans, increasing headlight voltage, etc

From the 72 Corvette wiring diagram the relay has 3 connections not counting ground,
1. a red/white that goes to the switches
2. Pink/black wire that goes to the ign plug on the fuse box
3. Orange/black that goes to a circuit breaker and on to the horn relay for full power.

On a newer style I thought
- run ign to post 86 (Connect it to the pink/white wire)
- 87 to the red/white output for full power to the switches.
- 30 to the orange/black wire for full power from the horn relay which connects to 87 when the ignition is turned on
- 85 to ground

Am I way off base on this? I would think it is more reliable than original on but what am I missing?