Topic: Power windows
in Forum: C3 Interior
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Lifetime MemberLost my power windows on my 74 yesterday. Both swithes are dead.
Well, I kind of figured that it has nothing to do with the switches; what are the odds of losing both at the same time...
Anyway, I looked at my wiring diagrams, and it appears that the common denominator (except for the wire at the fuse box; which I verified) is a fuse behind the firewall. I think I found it, but I'm not sure if that's the one.
A red (or dark pink) and orange wire mounted to a fuse (I think it's 30 amps) right on the top, driver side of the firewall.
Anybody knows how to do a diagnostic of this fuse ? If I connect my voltage meter to it, should I push on the switch to get a reading ?
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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
You need a continuity tester...multimeters often have them. It send voltage through the fuse and tells you if the fuse or circuit breaker is OK.
My '78's power windows operate through a 30 amp circuit breaker...not a fuse, but the cruise control, seat belt lamp and gauge lights operate through a 10 amp fuse. See if your dash lights and cruise control (if equipped) work...if not, it's likely that fuse.
One thing about circuit breakers...it could well pass current through it with a continuity tester but still be bad. I used to have a '67 Dodge Charger that had electric concealed headlight motors. They stopped working and I checked the 30 amp circuit breaker which tested OK with a continuity tester, but after installing a new circuit breaker, the headlights worked fine. Just because the breaker passed a light current through it, it couldn't handle the heavy amperage draw the electric motors placed on it. Your power windows could be doing the same thing.
Circuit breakers are cheap...only a few bucks at a supply store like NAPA.
My '78's power windows operate through a 30 amp circuit breaker...not a fuse, but the cruise control, seat belt lamp and gauge lights operate through a 10 amp fuse. See if your dash lights and cruise control (if equipped) work...if not, it's likely that fuse.
One thing about circuit breakers...it could well pass current through it with a continuity tester but still be bad. I used to have a '67 Dodge Charger that had electric concealed headlight motors. They stopped working and I checked the 30 amp circuit breaker which tested OK with a continuity tester, but after installing a new circuit breaker, the headlights worked fine. Just because the breaker passed a light current through it, it couldn't handle the heavy amperage draw the electric motors placed on it. Your power windows could be doing the same thing.
Circuit breakers are cheap...only a few bucks at a supply store like NAPA.
Thanks. That's what I meant; circuit breaker; not a fuse.
As far as I know, the fuse box looks good and the connection was clean, but I didn't test it with a reader. I'll try the circuit breaker now, since it's the only common denominator between the 2 switches.
Well, I replace the circuit breaker and ... same thing; which is nothing.
All my books (Chilton, Haynes, Service Manual) didn't mentioned power windows (unless I looked at the wrong chapters). Only the assembly manual had one page about it, but not much, really...
I guess my next step is to go test that ground and do a continuity test on the circuit breaker.
If that fails, I really have no clue...
Forgot to ask; in the meantime, can I pull them by hand ? I tried, but it wouldn't move at all. Do I need a can of elbow grease ?
in Forum: C3 Interior
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