72and86

Both Power Windows suddenly stopped working. There is power at the fuse box when checking that weird fuse relay thing. But from there my friend and I are stumped as no power seems to be getting to the switches.
In desperation we scraped away part of the brown wire leading to a switch and jumped it directly to the battery with a "jumper" wire…. BOTH windows WORKED (while only jumping the passenger switch wire directly).
From here we are stumped.
The 76 AIM or 76 Chevy Overhaul manual is no help. The Haynes manual is skimpy with wiring help too.
Any ideas?
(I have the entire center console area apart for restoration/repairs).

20mercury

For what it is worth, I have gone through a 2 or 3 power window switches on my 76. The passenger side is always the problem, maybe it draws too many amps and burns the switch up. Never had a problem with the driver side. I have rebuilt the power switches a couple of times which works pretty good, you have to bend the tabs out on the back, open the switch guts, clean it good and put it all back together. If I was smart, I would likely try to figure out why it is drawing more amps, maybe the window mechanism needs lubing?? Like my buddy said, he did not worry about the flickering overhead light in his volkswagon, until the headliner caught on fire!

I would check your electric circuit like any other electrical circuit and see what is missing. My bet would be the window switch in the console. But maybe not from rereading your description? I would get the wiring diagram and follow it out from good 12v power until you find the problem.

Hope this might help.

72and86

I can't seem to find a descent diagram. Besides the switches work fine once they get power...

F22

As far as wiring diagrams, there are a few vendors that sell beautiful laminated wiring diagrams. There is also one in the FSM or Factory Service Manual, which is a must have, along with any supplements. If you don't already have one, a multimeter is another must have when working with electrical problems. You could test switches for continuity as an example. Or using the DC volts and the wiring diagrams, see where you stop getting 12V. Without these tools, you're just flailing around.

'75

The thing in the fuse box is a circuit breaker. Sounds like either the window relay is bad or not getting a trigger with the key on. Make sure the trigger wire didn't get unplugged from the fuse box.

72and86

Where and what color is this trigger wire of which you speak?
I have to be gumby to even SEE the fuse box...

'75

Should be a pink and black wire and should plug into the ign tap, it may be piggybacked depending what other options you have.

20mercury

Ok, so much for the switch idea, you can look in the back of a Chilton's or Haynes manual for 68 to 82 Corvette and find a wiring diagram. I see one or the other at Auto Zone/OReilly's ect. from time to time. If Haynes is skimpy, try finding a Chilton's

I do not know another way other than tracing out the wire from the fuse to the switch and following it until you do not have good 12v and so isolating the problem area. Having a wiring diagram and following it out would be a logical approach to me.

This might help too:
https://www.corvetteforum.com/forums...gram-76-a.html

13611

I'd start with the circuit breaker. You may have very well removed the problem to check the power supply at the fuse box and then put the problem back in.

72and86

Thanks the link is very helpful.
Most stores don't carry any manuals for 1970s cars. I have the Haynes, AIM and Chevy Service Overhaul manual. This one:

http://www.ebay.com/itm/1976-CHEVROLET-SERVICE-AND-OVERHAUL-MANUAL-SUPPLEMENT-CAMARO-CORVETTE-CHEVELLE-/311092060599?pt=Motors_Manuals_Literature&hash=item486e8821b7&vxp=mtr
What else should I have? My 69 and 71, I could buy those thick GM manuals… I can't seem to find one for the 76.

F22

You need a 1974, because after 1974, they only did supplements for the '75's and 76's. The 1974 FSM is the manual you need, along with the supplement and it is the 'thick' one. I don't even have a Chilton or Haynes for the Corvette, because the illustrations are small and sucky (including the wiring diagram) and the real FSM has excellent tutorials at the beginning of many of the chapters. I also, still recommend a big, laminated wiring diagram in color. We have one, it was less than $20 and it's all color coded and enlarged. Makes it much easier to figure out. The FSM wiring diagram is useful too.

72and86

this one?
http://www.ebay.com/itm/1974-Chevrolet-Chevy-Car-Light-Duty-Truck-Overhaul-Manual-/381000197387?pt=Motors_Manuals_Literature&hash=item58b561a50b&vxp=mtr

F22

No, that's an overhaul manual

http://www.themotorbookstore.com/1974chevrolet.html

72and86

Thanks. Ordered eBay for $19 shipped.

72and86

OK, the above are pics of my fuse box which I can barely access without turning into a Twizzler… Are these the correct connections…per your description? The car has very common option available in 1976.




Then there's the brown wire connector just hanging. I didn't see any widowed connectors for it…. My apologies, Im not good at this sort of stuff...

'75

That looks right, however you should do something about the foil on the hazzard fuse before you have an electrical fire.

'75

The brown is probably for an accessory power for an option you don't have.

20mercury

For my 76, my experience and this may not be the cheapest way to go, not sure I would this again, I ordered the factory service info from Helm, which is the GM factory manual supplier and got 5 books
74 service manual
76 service manual supplement
74 overhaul manual
76 overhaul manual supplement
76 wiring diagram (really a booklet)
So, I believe that comprises what GM would say is the factory info.

I see this stuff above on ebay from time to time. I also have Chilton's from ebay that covers thru 76 Corvette and another through 82 I think. All of these wiring diagrams I think are a little tricky to follow particularly when they go to another page, I like using a highlighter I would check ebay and order it. Hope this might help.

72and86

Yeah I gotta get one of those tiny fuses.
So I guess I'm in to it for ordering a PWR Window relay for $27…
(Cross my fingers…)

Kris Tunetso

Assuming I'm remembering my 1976 wiring diagram correctly, Pink and black are your power windows, the Grey wire with the black connector below that should be for the Map Light on your review mirror, and the Brown wire piggybacked off that should go to your rear window defogger switch. For what it's worth, I'd switch those 2 around so that the defogger is going to the fuse block, and the map light is the piggyback. Defogger uses a larger gauge wire and could possibly burn out the map light extension by drawing too much power through it. You want to go from large-gauge wires to smaller ones, not small to large.

I highly suggest you buy a wiring diagram set from Dr. Rebuild. It's full color, lists the correct wire gauge and shows the actual connectors so you can identify exactly what you're looking at. Makes it really easy to identify what's what when you find something unplugged.

Your service manual and supplement will pay for themselves the first time you use them. I'm normally the type to search my problems online, but the book is just so handy to have right there in the shop, and you don't have to worry about how to word your search query.

See here for additional recommended literature to purchase.