1985 944 ac problems
06-18-2011, 12:56 PM
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Track Day
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1985 944 ac problems
I just installed a new compressor and drier, charged it with 2 1/2 cans of freeze 12. Problem is, that the clutch on the compressor is not engaging. Does anyone have a clue what might be causing this? Help its hot in Alabama.
06-18-2011, 03:49 PM
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Well, I'm having the same problem and have diagnosed it to a bad evaporator temperature sensor. Used one is on it's way. If you have a multimeter check the resistance at the connector, it should be around 150ohms. The connector has 2 wires, one white/blue and one white/green. It's under the passenger side dash on the evaporator box. Pull the glove box out so you have easier access.
That's my problem, but of course you could have another issue as well. Have you tried to jump off the a/c clutch? If it's working, then I would check the operation of the A/C relays. If they're working, check the A/C amplifier. It's a little black box with a "C H" marking on it. The black/white wire that comes out of the wiring connector is the wire that feeds the compressor clutch fyi.
There is a website that has the shop manuals upload, do a google search and you should find it. You can get the A/C wiring schematic from the electrical shop manual. Don't get your hopes up though, the A/C troubleshooting section in the manual is for the later cars, not the early cars.
That's my problem, but of course you could have another issue as well. Have you tried to jump off the a/c clutch? If it's working, then I would check the operation of the A/C relays. If they're working, check the A/C amplifier. It's a little black box with a "C H" marking on it. The black/white wire that comes out of the wiring connector is the wire that feeds the compressor clutch fyi.
There is a website that has the shop manuals upload, do a google search and you should find it. You can get the A/C wiring schematic from the electrical shop manual. Don't get your hopes up though, the A/C troubleshooting section in the manual is for the later cars, not the early cars.
06-18-2011, 04:13 PM
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You're going to need some sort of wire with alligator clips on the end. Disconnect the wire by the a/c compressor, connect you're alligator clip, and connect the other end straight to the positive post on the battery. When you do this, you should hear the clutch engage. If it doesn't, then your problem is with the clutch.
Mine works fine, so I've never had to deal with it.
