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1978 ac help

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Old Aug 20, 2014 | 10:03 PM
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Default 1978 ac help

Blower works, AC fuse good. Move temp selector to hot and get hot air, move to cold and get cooler air. Visually checked switch behind glove box and dog moves switch in and out. Get air from defrost, vents or footwells as selected.

I have no power to the green wire on the compressor. Don't see a wire diagram in AIM. I see a swtch with. 6 or seven wires but I dont know what wire does what. Don't know how this switch works either but I guess this is the place to start.

Anyone know where I can get a wiring diagram and operationg description of how this works?
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Old Aug 20, 2014 | 10:15 PM
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There is a post from papawana, he or she will send you the wiring diagrams. Do a search for 68-82 wiring diagrams for anyone. You have to PM.
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Old Aug 20, 2014 | 10:48 PM
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could be low on freon, causing the low pressure switch to cut power out to compressor, you can bypass it with a jumper and then check for 12 volts.
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Old Aug 21, 2014 | 06:51 PM
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Originally Posted by lvmyvt76
could be low on freon, causing the low pressure switch to cut power out to compressor, you can bypass it with a jumper and then check for 12 volts.
I agree.
In the pic, center right side.
Fitting with the wires. Unplug it and jump. You'll need to do that to add Freon, too.
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Old Aug 21, 2014 | 07:27 PM
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Default Ac

Low on refrigerant is probably the cause. When it drops below 45psi the switch turns off the compressor. You do not have to jumper it to add refrigerant. Just add refrigerant at low pressure port, when the pressure reaches 45-50 psi the compresser will engage. Be sure to have AC on max and blower on high. Obviously you will need to see why the refrigerant leaked out.
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Old Aug 22, 2014 | 09:37 AM
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Thanks all. When I jumped the switch the compressor clutch pulls in. Now to get a charge of freon.
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