AC quit working

J_lope82

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So AC was working had been working fine for about a month(just bought the car). Friday I went out for a cruise. About 1 hour into the cruise ac start coming out hot. I shut it off for a minute and turn it back on, it started cooling again then quits again a few minutes later. Yesterday I tried it again it did not work at all. This morning I turn it on and it started to work and then quit after about a minute. It came back on again on its own intermittently then got hot and stayed hot. I started to dig into the issue. The clutch is not engaging. The free on pressure is 95 psig with ac off. All fuses are ok. I hooked up forscan and when I turn the ac on it says ac on and clutch is on and both pressure switches ok. I did a key on engine off self test and it passed. I checked voltage to the ac clutch and it’s not getting voltage. So at this point I’m thinking I have a bad constant control relay module. What do you all think? I heard mixed things about this relay module. I just want to hear what you all have experienced and get your thoughts before I buy a $150 module. Thanks in advance.
 

J_lope82

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Do yourself a favor and hook up a set of manifold gauges, high side and low side, then jump the low pressure switch connector and see what the pressure reads.
So checked the low side with the gauges and it was 95 psig(ac off). The high side hose is messed up so I can’t get a reading on the high side. I’ll try to jump the low side switch. What am I looking for?
 

d.garza18

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So AC was working had been working fine for about a month(just bought the car). Friday I went out for a cruise. About 1 hour into the cruise ac start coming out hot. I shut it off for a minute and turn it back on, it started cooling again then quits again a few minutes later. Yesterday I tried it again it did not work at all. This morning I turn it on and it started to work and then quit after about a minute. It came back on again on its own intermittently then got hot and stayed hot. I started to dig into the issue. The clutch is not engaging. The free on pressure is 95 psig with ac off. All fuses are ok. I hooked up forscan and when I turn the ac on it says ac on and clutch is on and both pressure switches ok. I did a key on engine off self test and it passed. I checked voltage to the ac clutch and it’s not getting voltage. So at this point I’m thinking I have a bad constant control relay module. What do you all think? I heard mixed things about this relay module. I just want to hear what you all have experienced and get your thoughts before I buy a $150 module. Thanks in advance.
Common issue with these cars is the module. I’d say try it out, if it doesn’t work return it
 

lwarrior1016

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The static pressure doesn’t matter much, we need to see what the pressure is with the compressor running. Right now we are trying to force the ac compressor to come on.

Start the car, make sure the ac is turned on full blast, then unplug the low pressure switch and test for voltage. One side should have power, if it does, then jump the harness from one pin to the other. The compressor should come on, if it does not, then check the compressor connector for power.
 

RAU03MACH

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In a way you need both sides to read high low
If pressure is equal you have a block in the system
If so
Start with orfic tube filter
 

J_lope82

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The static pressure doesn’t matter much, we need to see what the pressure is with the compressor running. Right now we are trying to force the ac compressor to come on.

Start the car, make sure the ac is turned on full blast, then unplug the low pressure switch and test for voltage. One side should have power, if it does, then jump the harness from one pin to the other. The compressor should come on, if it does not, then check the compressor connector for power.
So with forscan I was able to see the clutch on command at the pcm which would lead me to think the selector switch, low and high pressure switches, circuits and free on are where they need to be. I did check the voltage at the clutch and there is no voltage when I turn on the ac.
 

J_lope82

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In a way you need both sides to read high low
If pressure is equal you have a block in the system
If so
Start with orfic tube filter
I think they are equal because the compressor is not kicking on. My high pressure gauge is not working properly.
 

RAU03MACH

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I think they are equal because the compressor is not kicking on. My high pressure gauge is not working properly.
you need to hook up gages high and low side to look at the pressures to actually see what is going on
I have ran into problems that the orifice filter is plugged up with all kinds of junk oil o ring particles
stop leak you name it
so it causes it to freeze up at that tube just a tiny bit of Freon is getting through enough to when you shut it off it has enough to pressurize the system
but you do need readings from both sides
 

07GtS197

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I bought my 02 Gt with a bad ccrm. What happens is the relays will burn up a pin. So I bought a new relay and soldered it in myself and it worked until I sold it. I’d recommend doing it yourself if you can solder.
 

J_lope82

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I bought my 02 Gt with a bad ccrm. What happens is the relays will burn up a pin. So I bought a new relay and soldered it in myself and it worked until I sold it. I’d recommend doing it yourself if you can solder.
I bought my 02 Gt with a bad ccrm. What happens is the relays will burn up a pin. So I bought a new relay and soldered it in myself and it worked until I sold it. I’d recommend doing it yourself if you can solder.
 

J_lope82

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I can solder just wouldn’t know where to get the correct relay with the same amp rating and that will fit in place.
 

lwarrior1016

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Don’t worry about forscan. That’s a good tool, but it doesn’t tell you exactly what’s going on. Try those checks I outlined above and let us know what it says. It’ll only take a couple minutes.
 

J_lope82

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Well after more troubleshooting I saw that I have 13.5 volts to the compressor clutch and the clutch is not engaging.
 

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