Heat and AC no longer work. Help.
#1
Heat and AC no longer work. Help.
Hey guys,
My heat and ac no longer work. When I slide the mode selector nothing happens. When I turn the **** for the fan speed, nothing works either. I checked the obvious fuses under the dash twice. Any relays or fuses I'm not aware of? Any other suggestions before I go to the stealership? TIA
92 camaro RS V6
My heat and ac no longer work. When I slide the mode selector nothing happens. When I turn the **** for the fan speed, nothing works either. I checked the obvious fuses under the dash twice. Any relays or fuses I'm not aware of? Any other suggestions before I go to the stealership? TIA
92 camaro RS V6
Last edited by EVL TTWN; 10-12-2006 at 01:18 PM.
#2
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
The stealership is utterly useless in cases like this, except for making your car faster by lightening it. Their weight reductions are centered primarily in the neighborhood of the driver's wallet.
Take out your AC control head. You'll observe a single harness that plugs into it; there'll be a group of about 4 wires that goes off one way, and a single brown wire that goes off a different way. That brown wire is the power feed to the whole system. Follow it back into the dash from the control head; about 12-15" in, you'll come to the remains of something, that used to be a connector of unbelievably stupid design. Cut off however little of the ashes are left on the ends of the wires, and replace it with a pair of the BIG THICK HEAVY-DUTY yellow insulated slide terminals. Not just yerbasic ordinary weenie ones; remember, BIG THICK HEAVY. Alot of current flows through there.
Take out your AC control head. You'll observe a single harness that plugs into it; there'll be a group of about 4 wires that goes off one way, and a single brown wire that goes off a different way. That brown wire is the power feed to the whole system. Follow it back into the dash from the control head; about 12-15" in, you'll come to the remains of something, that used to be a connector of unbelievably stupid design. Cut off however little of the ashes are left on the ends of the wires, and replace it with a pair of the BIG THICK HEAVY-DUTY yellow insulated slide terminals. Not just yerbasic ordinary weenie ones; remember, BIG THICK HEAVY. Alot of current flows through there.
#4
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Yeah I've had 2 cars of my own, and 5 others in my immediate family including Caprice, Cutlass, Monte Carlo, Celebrity, etc. that I can remember off the top of my head, that I've fixed this.
Next, after you get that one going, look at your blower motor. You'll find a purple wire and a black wire. Follow the purple wire about a foot, you'll come to the blower motor high-speed relay. You'll find a thick red wire in the same plug. That's the hard battery feed to the high speed relay, that powers the blower motor in the high speed ONLY. Follow that thick red wire about 18" or 2' over the hump toward the driver's side. About right above the pass side valve cover, you'll find another extremely stupidly designed connector in that big thick red wire. Which when that one burns up, you'll have no high speed. I've changed out even more of those. That one though, if every time you change your oil, you just unplug and replug it (kind of scrape the connection clean), it will last alot longer.
In both cases, the metallic part of the connector is too small, and the plastic part is responsible for maintaining the connector tension. So, when lots of current flows, they eventually develop a little corrosion, and the connection gets hot; when it gets hot, it melts the plastic; when the plastic melts, the connection gets a little worse; when the connection goes bad, it gets hotter faster; when the connector gets hot, it melts the plastic; ..... I think you can figure out where this is going.
The moron that "designed" those ought to be forced to go around to every car that they've burned up in, and fix them. The idea of using the plastic as the tension spring is one of the most boneheaded imbecilic pieces of "engineering" I think I've ever seen; and as an engineer, I can assure you I've seen more than my fair share.
Next, after you get that one going, look at your blower motor. You'll find a purple wire and a black wire. Follow the purple wire about a foot, you'll come to the blower motor high-speed relay. You'll find a thick red wire in the same plug. That's the hard battery feed to the high speed relay, that powers the blower motor in the high speed ONLY. Follow that thick red wire about 18" or 2' over the hump toward the driver's side. About right above the pass side valve cover, you'll find another extremely stupidly designed connector in that big thick red wire. Which when that one burns up, you'll have no high speed. I've changed out even more of those. That one though, if every time you change your oil, you just unplug and replug it (kind of scrape the connection clean), it will last alot longer.
In both cases, the metallic part of the connector is too small, and the plastic part is responsible for maintaining the connector tension. So, when lots of current flows, they eventually develop a little corrosion, and the connection gets hot; when it gets hot, it melts the plastic; when the plastic melts, the connection gets a little worse; when the connection goes bad, it gets hotter faster; when the connector gets hot, it melts the plastic; ..... I think you can figure out where this is going.
The moron that "designed" those ought to be forced to go around to every car that they've burned up in, and fix them. The idea of using the plastic as the tension spring is one of the most boneheaded imbecilic pieces of "engineering" I think I've ever seen; and as an engineer, I can assure you I've seen more than my fair share.
#5
Thanks for taking the time to write such an informative post! I've printed what you wrote and will trying this out hopefully this weekend. On a side note, I lost my blower low speed years ago.
You wouldn't happen to know how to fix my guage cluster would ya? At 60mph, the needle sticks and doesn't go any higher. My RPM needle also sticks at the same time the speedo needle sticks.
You wouldn't happen to know how to fix my guage cluster would ya? At 60mph, the needle sticks and doesn't go any higher. My RPM needle also sticks at the same time the speedo needle sticks.
#6
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Re: Heat and AC no longer work. Help.
bringing this back fromthe dead. I am having the same issue. I am getting power to the red wire at the relay and I did notice that the blower resisitor was hot to the touch. The blower motor gets no power at all and I get nothing from the HVAC control panel. I swapped out relays and HVAC panels and still get nothing.
#7
Re: Heat and AC no longer work. Help.
Thought I'd add a few notes. I replaced the blower motor before I thought to look this thread up. I read through this, then checked the relay (it was fine). I cut those two faulty connectors and replaced them with good connectors, and it works! I have an '86 firebird. To sum it up: the first connector that needs to be replaced is behind the control unit on a brown wire. The second one is near the relay on the passenger side (not driver's side); it's a red wire. The bad connectors look like an elongated box shape. They appeared fine at first, but upon replacing them it fixed the problem.
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