# 96 hardbody ac works on and off



## danielguin (May 15, 2016)

Replaced compressor. dryer. expansion valve. dash switches . pressure switch and relay. I took it to the dealership to get it vacuumed and charged up. The problem is reverse of what I have usually read. Mine works fine at idle. Can start truck no matter what the temp is outside let it idle and it will work flawlessly. Get in it and drive it the compressor cuts off after 5 to 30 minutes. Will not come back on until i let the truck sit for a while. This started before I replaced everything. The condenser and evaporator core was flushed to make sure ther was no blockage. What is left that would cause this? I even went as far as taking the thermostat out so the temp wont hardly get off cold. New antifreeze and radiator. I am stuck on this one.


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## jdg (Aug 27, 2009)

I'd take it back to get it checked to see if the A/C is overcharged. That'll wreck stuff right now. I don't know if the HB has a "blowoff" valve for the A/C like my Honda does. I'd assume it does but if it is overcharged, your compressor is kicking out before pressures are getting too high...which is a good thing.


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## smj999smj (Jan 1, 2006)

When you had access to the evaporator core, did it have a thermistor (a.k.a. "thermal amp")? It would be a little sensor with two wires that gets pushed into the fins of the evaporator core that shuts off the compressor if the core freezes or gets too cold. If it does, that could be an issue, as well.


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## Roader (Nov 9, 2014)

Looks like there's a small PCB that has solder joints that can open up too:

https://www.youtube.com/watch?v=YbGHIaHGBaE


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## danielguin (May 15, 2016)

I saw that and tried to google what it was so i put it back and didnt think twice about it. I will try to pull the wires out of the coil to see if there is a difference. The whole mess needs to come out to change it but I believe I can get to the wires themselves without taking it apart.


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## Cusser (Apr 16, 2004)

danielguin said:


> Replaced compressor. dryer. expansion valve. dash switches . pressure switch and relay. I took it to the dealership to get it vacuumed and charged up. The problem is reverse of what I have usually read. Mine works fine at idle. Can start truck no matter what the temp is outside let it idle and it will work flawlessly. Get in it and drive it the compressor cuts off after 5 to 30 minutes. Will not come back on until i let the truck sit for a while.


Question:
When the compressor cuts off, is it still getting 12 volts positive to it but the AC magnetic clutch just doesn't engage? I think this is the main question.

If not, must trace backwards through the circuit, pressure switches, etc. to find the component that is stopping the positive voltage from getting there.


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## danielguin (May 15, 2016)

I had finally taken it to the dealership and they charged me nearly 200 for a bit of freon. And after them keeping it for 3 days it worked perfect all 3 days. I drive it home and 12 miles into the trip home it quits. I take it back to the dealership and it works perfect. Took it back there again today because it kept on messing up all day and lo and behold it will not act up while they have it. I believe I will get a catholic priest to do an exorcism on it and sprinkle it with holy water because that is about all that is left to do.


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## Cusser (Apr 16, 2004)

Cusser said:


> Question:
> When the compressor cuts off, is it still getting 12 volts positive to it but the AC magnetic clutch just doesn't engage? I think this is the main question.


See above. If so, need to check if AC clutch "gap" is too large, or if AC clutch coil circuit "opens" when it gets overheated.

You have an intermittent, must troubleshoot when it's NOT WORKING.

On the other hand, you paid dealership $200 to fix the problem, and they did not; if they told you this was a fix, and not a guess, they still should fix for that price. Push back with them, and if you paid with credit card, consider disputing the charge. Basically they charged you money, and didn't fix; I had similar issue with GM dealership over a sunroof that they had no idea how to fix, had to fight to get my money back, but did.


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## pontgta (Feb 11, 2008)

if pressures are correct, I would check the power going to the compressor, and might have to rig some sort of light(temporary) to check when not working. I think you might have a faulty compressor(clutch is about the same price of a reman compressor) but I would check to make sure.


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