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Discussion Starter · #1 ·
I have been trying to find out how the A/C comp. on my 78 Camino is wired, what kind of switch cycles the compressor. Then the next thing I need to know is, how do I re-wire it, or what do I need to do, to make it work off of a pressure switch?
Before you get on me about doing a search , I have, I guess I do not know what words to put in to get the answers that I need. Thanks for your help on this issue.
 

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the compressor gets it power from the heater control switch then goes through the pressure switch then to the compressor.dont eliminate the pressure switch its there to protect the compressor
 

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Discussion Starter · #4 ·
Thanks for the wiring diagram. No I do not want to get rid of the pressure switch, I am trying to find it. There are no switches on any of my lines or drier. I follow the green wire back to the fire wall, and it disappears into the AC box or inside the car. I have never seen this before. All the AC systems that I have worked on has the switches out under the hood, in the system some where. I was told by someone the it worked off of the temp from the evaporator. This does not sound right to me. What I got into was when I had it down to the Silver Springs show this past September, in started squeeling the belt every time it kicked on the compressor, and it ate the belt. I put on a new belt, but it just got worse. Well I figured my compressor was going bad, and it was time to up grade the AC system, but what was really wrong was the orfice tube was stopped up. The compressor was running with to high of head pressure, and nothing to control it, to keep it from cycling. I replaced the orfice tube, recharged the system, and it works fine now. So I am trying to find my presure switches to keep this from happening again.
 

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The 78 does not have a pressure cycling switch, but does have a thermostaic cycling switch mounted on the evaporator case with a capillary tube attach to the evaporator outlet that senses temperature rather than pressure to cycle the compressor.
 

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i have a 78 in my shop right now with a pressure switch,did they come both ways? it has a 8 /78 build date
 

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Probably someone has swapped it over. When I started having problems with the thermostatic switch on the 79 I swapped it over to the pressure cycling switch.
 

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Probably someone has swapped it over. When I started having problems with the thermostatic switch on the 79 I swapped it over to the pressure cycling switch.
Correct.
 

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Discussion Starter · #9 ·
that is the info that I needed. Now how is the correct way to re-wire around it? That is to make the pressure switch work correctly.
 

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Screw a pressure switch on to your accumulator. Take the two wires off the thermostatic switch and attach them to the pressure switch. You will probably need to adjust the pressure switch cutoff pressure by turning the center screw on the switch about 1/4 turn counter-clockwise to obtain a cutoff of around 21-22 psi.
 
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