Hey , folks . Working on A/C on HHR for a friend . Here's what it's doing and not doing �� air is charged , while air is on , the high side of compressor pumps to @ 450 psi at that point I'm assuming the high side switch turns compressor off . To avoid a pressure related catastrophe ? Air blows like the heat is on , not the air . I thought perhaps the expansion valve was plugged ? So I replaced it and recharged , guess what ? , that was not the problem . Still doing the same thing �� any thoughts would be appreciated . Thanks Jim

 

I broke this of into a separate thread.

I'm not sure if your description is too technical a not technical enough, but I don't understand the problem.

Are you saying that the compressor is working, but not cooling? It works for a while but quits?

The A/C will not operate if there is a CEL, usually a P0128 is the cause.

Year and model would also be helpful.

 

2006 hhr lt I believe . Does not blow anything but hot air ( like the heater is on , not the air . And yes the compressor is working . Pressure cycles to about 450psi on the high side gauge and kicks out . Pressure slowly equals out while compressor is off and then does the whole cycle over .no cel or codes .

 

What about the low side reading ?

Also, is the cooling fan working correctly ? Should be blowing on the condenser when the AC is engaged. No air movement across the condenser would cause high pressure readings.

 

Welcome to the site James, check the blend door actuator

 

The only way that the pressure can be regulated is with the clutch. If the pressure switch senses too low it shuts the clutch off. If the pressure is too high r134a is vented to atmosphere, meaning it would need recharging.

You seem to be saying that the compressor is always running, but pushing hot air?

The heater core is always hot, if the blend door is stuck that would cause dehumidified hot air to come into the cabin. Does that help?
The outside air comes into the HVAC box on the cold side and mixes with heated air when commanded.
From Mitchell:

 

The low side reading drops to @ 35 psi as the high side is climbing and no matter how long I let it idle the cooling fan does not come on . The gauge in the dash remains in the safe zone and doesn't show overheating . So I figured it wasn't getting warm enough to call for the fan . Is there a way to test to see if the fan is faulty ? Thanks

 

Hi
Haven't checked the blend door yet . Although when I turn it from
Cold to Hot the air gets really hot , to the point where you don't want to hold your hand there long so it is hotter when changed to heat . I realize that in itself doesn't mean the blend door is functioning properly . I'll need to have a look . Thanks

 

Any time the AC compressor is engaged (AC or defrost mode) the cooling fan is supposed to turn on and stay on. The cooling fan is not temp controlled when in AC mode.
You need to determine the reason for the fan not turning on before doing anything else.

Fwiw. The analog or needle gauge on the dash is not very accurate. Always look at the digital numbers on the DIC for the actual temperature. The cooling fan is set to come on at 217F when not in AC mode.

 

Bingo! The radiator cooling fan is the gremlin.

At this point you need to know which model you are working on because the fans are different. Can I assume that you can tell if the car has a turbo? That would make it an SS, with different parts from a LS/LT.