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I swear that when I get through with this thing, I'll be able to rewire my '76 in my sleep. Anyway, the power windows don't work up or down. I replaced both switches, and both window motors. Regulators are both good, so nothing is binding. They worked for awhile , and then when I took the dash out and started rooting around all of the wires there then they stopped. I traced all of the switch wires, and some go to the relay. Could that be a problem? When I was moving the wires around the fuse box, like a dumbass I had the battery still connected, and a few sparks went flying , so I thought maybe I fried the relay. After disconnecting the battery, still nothing so I thought maybe it's the 30 amp circuit breaker. If it's that I looked all over for it from the relay to the fuse box. Still couldn't find it. Anyone have a pic of it or tell me how to find it? The schematic looks pretty easy but with all of that other wiring in the way it gets tough. Do you think I should replace the relay? And how about the 30 amp circuit breaker if I can locate it? Thanks
On your line diagram you will see the relay is externally grounded by a #12 BLK wire circuit #150. Can you find the original location where the relay was mounted? Most #150 circuits are body grounds. The relay also could have been secured by a single fastener through the relay directly to the body.
I think you will find the circuit breaker in the engine compartment on the fire wall. The red wire is the power wire and it comes off the horn relay terminal.
Dale
Window motor relay, firewall circuit breaker are good possibilities. Also, since you created a 'dead-short' in the system and "sparks flew", you may have fried a 'fusible link" in the system. If you are not familiar with fusible links, do a SEARCH for that item and read some past posts on them. GM used them in several locations to protect wiring and components from 'dead-short' situations....whether due to hardware failures or from "cockpit" trouble.
Window motor relay, firewall circuit breaker are good possibilities. Also, since you created a 'dead-short' in the system and "sparks flew", you may have fried a 'fusible link" in the system. If you are not familiar with fusible links, do a SEARCH for that item and read some past posts on them. GM used them in several locations to protect wiring and components from 'dead-short' situations....whether due to hardware failures or from "cockpit" trouble.
The only fusible link I know of is near the starter somewhere. I'll check my schematics for more. Thanks
On your line diagram you will see the relay is externally grounded by a #12 BLK wire circuit #150. Can you find the original location where the relay was mounted? Most #150 circuits are body grounds. The relay also could have been secured by a single fastener through the relay directly to the body.
Yeah I saw that. Mine does not have a grounding wire, but is fastened by a screw (which I cleaned up) and fastened to the tunnel
I think you will find the circuit breaker in the engine compartment on the fire wall. The red wire is the power wire and it comes off the horn relay terminal.
Dale
Thanks. I will look for it there. It looks like one of the two
I believe you will find the circuit breaker in the upper left position of your fuse panel. It looks like the silver box with 2 round prongs coming from the bottom (see above photo). If you need one, PM your address to me and I will send it to you.
Also suggest you purchase Doc Rebuild's "oOSOEZ" wiring charts. They are 11x17 laminated charts that have photos of all of the connectors in your year C3 as well as color wiring schematics for every circuit. They have been invaluable when working on my 77, allowing identification of "mystery parts".
Last edited by Rotonda; May 5, 2018 at 06:14 AM.
Reason: Addition
Power for the A31 Power Windows option came from the horn relay, so a fusible link at that site may, or may not, be in play. From there, it travels to the circuit breaker on the firewall, goes to the fuse panel, and then to the switches. Ground wire for that system is a lug screwed to the inside of the upper driver's door hinge plate.
OK , I located the circuit breaker and pulled it. I can't tell if it's good or bad (see Photo). I ordered a new one, and should be here in a few days. So when I install the new one, do I just see if I have any voltage by putting the Pos (red) cable of the voltmeter on one of the tabs on the circuit breaker tabs in the fuse panel? That's where I pulled it from, upper left of panel. If I get voltage there, then test again at the relay? If not any voltage there, then the wire between has to be bad right? If it's good and have voltage there, do I check from another tab on the relay towards the switches right? I'm sorry , but auto wiring is not my strong suit. Thanks
Actually, you can do that now to see if there is positive voltage at either connection for the circuit breaker. There should be one of those terminals that is 'hot' when the ignition is turned to 'ON' (first detent...before the START position). If you find that neither terminal is hot, chances are that your circuit breaker is fine and there is a problem getting power ahead of that location in the circuit.
You can also test that circuit breaker easily with your meter. It should have continuity across it (zero ohms resistance, or very close to zero). Those breakers should go to open circuit (infinite resistance) temporarily if they see too much current flow (like an inadvertant dead short with a screwdriver). It's entirely possible the breaker could have popped, and then not reset itself correctly. In that case you should see high or infinite resistance across it. If you have continuity on the breaker, there's no reason to replace it.
With the breaker installed in the fusebox, you'd want to set your meter to voltage, ground your black lead (the kick panel screw usually works nicely), and check for 12v on both sides of the breaker. As mentioned earlier, if both sides have no power, the problem is someplace upstream of the fusebox. If only one side has 12v, the breaker is the trouble. If both sides have 12v, the trouble is somewhere downstream of the fusebox.
With the breaker installed in the fusebox, you'd want to set your meter to voltage, ground your black lead (the kick panel screw usually works nicely), and check for 12v on both sides of the breaker. As mentioned earlier, if both sides have no power, the problem is someplace upstream of the fusebox. If only one side has 12v, the breaker is the trouble. If both sides have 12v, the trouble is somewhere downstream of the fusebox.
When I look at my schematic , it looks like it gets power directly from the alternator. Thanks, I will check all of these tomorrow
Electrical Delelimma, Again
