A/c compressor not kicking off...

[Dtaber8604]

I have my A/c blowing cold as ice but it is not cycling off (89 ram 50)... Trying to avoid taking it to a shop but any suggestions on where the high pressure switch is and how to test it? The expansion valve is against the firewall and it has a copper rod (looks like some sort of a thermostat) that slides in the cold hose. Hopefully this makes sence to someone and will be an easy fix. Thanks!

[pennyman1]

that is not the problem - your temp sensor in the evap core is bad and saying to keep the clutch on the compressor engaged, or the temp controller failed

[recian]

You're lucky. Mine won't stay on :( Keeps wanting to kick on and off randomly as i play with the controller's connector.

[Dtaber8604]

I got lucky and got it all to work. I sprayed my compressor with wd-40, hit it with a hammer a few times, cleaned all my connections to include the evap temp sensor and it started cycling like it was supposed to. Been fighting my blower motor lately. Changed the $45 resistor (5 day special order) just to find out it was a bad ground.... It's blowing ice cold now and it's actually colder than my 04 crew cab 2500hd gmc! Thanks for all the help this site is about the only place I can find ppl that even know what these trucks are!

[Dtaber8604]

Recian,

Sounds like the relay could be getting hot or something to that nature. I would start at the pressure switch and work my way forward if your 134a gauge readings are where they are supposed to be. Mine took just over a can of freon and it was perfect.

[camoit]

if the high pressure cut off switch was not replaced with the new 134 pressure switch that can be the problem. As the good stuff R12 runs a higher pressure then 134 so it thinks it's low

[BradMph]

Got thermostat for the AC? Looks like a hot summer for Recian. Get to break in them new cables i sent you. :.) I like to turn on heater and AC and let them duke it out for an hour or two.

[recian]

haha those cables are holding up good. Funny I dont' need that a/c blank anymore that you sent me lol I've actually got a problem with the connector at the control unit or the socket in the control unit. I shouldn't have disconnected it when I put the box in. It was a tight fit but I could have done it... I'm trying to fix it as fast as I can. These 100% humidity 80+ degree days suck. I wana drive the truck while my sentra is at the muffler shop so I can't do the exhaust work until that's done. Plus I think I need some shocks. It rides like a boat and bottoms out alot on speed bumps and the driver side sits lower than the passenger side lol What's worse with not having a/c is it'll rain for 10 minutes then the sun comes out and it gets super sticky and the a/c in the building sucks ass so if I want relief I have to pray someone didnt leave the bathroom door open and let the air out or go for a test drive and pray the customer's a/c works lol

[pennyman1]

BTW - it is the r134a that run at higher pressures than the r12 - that is why if your hoses are looking bad you should replace them to prevent blowoff. Oil amounts are also more critical as too much oil will send the pressure soaring. If retrofitting an r12 system, either flush the system to remove all traces of oil or use ester oil - it is compatible with r12 compressor oil. Pag oil that is normally used in r134a systems reacts violently and will damage an r12 A/C system.