My Air Conditioner is blowing hot air and I am not getting any codes (all controls are working). I did some research here on the forum but I didn't get any answer for my problem. My AC clutch is not coming on, so I had my car charged with freon and still won't come on (it was empty). I need you guys help on how to check the (low/high side)switch and location. Thanks

 

I know on every (old ) GM I have worked on, you can short out the 2 leads on the plug that goes to the pressure switch ( with the pressure switch unplugged) and the compressor will come on regardless of whether or not there is any refrigerant in it. You may also want to check and make sure the wires are making there way to the clutch and plugged in on the compressor. Check for voltage on the wires when A/C is turned on. Low side and high side should be equal when the system isn't and hasn't been running. Not accurate, but a good rule of thumb is the pressure should equal the temperature (or somewhere near it ) when the system is settled. 90 degrees = 90 psi on both sides. Check fuses.

 

If it was empty, did they check for a leak by adding dye? It shouldn't be empty. I'm not sure, but if there is a leak somewhere, it might not throw a code, because codes are only related to electronic issues. Maybe I'm wrong, but it seems like the freon is leaking from somewhere, and you need to find out where that is.

 

If it is leaking, It should leave an oil trace there which will gather dirt and dust. I would check for codes and then re-set them if you find any HVAC codes. I forgot the computer monitors everything in these cars.

 

First thing you should do is display and post any/all DTC codes set. The A/C system is electronically controlled by the cars computers. For example you don't say if you have the auomatic or manual HVAC controller .... but regardless, when the HVAC wants the A/C compressor engaged it sends a message to the PCM "requesting" the PCM to turn on the A/C compressor. The PCM decides if it will turn on the compressor, and posts codes when it sees problems (such as it commands the compressor on and it does not come on ....

List the codes and let's see what the computers are telling us.

Ralphyboy .... the PCM monitors refrigerant pressure ... it will throw a P0530 if the refrigerant pressure is too low or too high.

 

well, recently I had a Cam and Headers done. It may have leak out when it was done. They did put dye to check for leak, the tech had to stop working on it due to burn on his hand (from my headers). Does the engine has to be running to short out the leads?

 

I am not getting any codes at all. I have dual zone control.

 

No codes ?????????????

OK, try this ... engine running ... set the driver's temperature down to 60 degrees (as low as it can go) on the HVAC..... what is the status of the A/C lamp on the A/C button ???? ON or OFF, or BLINKING and then OFF ????

What is your display for the outside temperature ??? Is the outside temperature incorrect and below 40 degrees ???

It is possible the interior temperature sensor is bad .... the first test (60 degree setting) will test that .....

The outside temperature sensor also affects the A/C .....

No codes .... at all ???? In a Corvette ???? Wow .....

 

Ok...I tried what you said, 60 on high(fan) with the A/C light on (steady - not blinking). Outside temp seems to be accurate 71 degrees today and 80+ couple a days ago. I have codes but it was because I haven't put my TPMS on my tires....(B0-RFA) U1096, U1016, C2120. Thanks ED

 

WHAT HAPPENED WHEN YOU SET IT TO 60 ????????????????

Did it blow cold air or warm air ??????

 

warm air

 

Yes, but I'm not sure if you can short the leads on a C5. Bill Curlee might know. I don't have schematics or factory service manual on C5. When A/C system tells compressor to turn on, the voltage goes through a pressure switch to make sure it has enough refrigerant for the compressor to come on without damaging it. From the pressure switch, it goes to the compressor. If you short out the switch and the compressor turns on, it means the pressure is too low or the switch is defective. You should measure voltage at the pressure switch to make sure the climate control system is sending voltage telling the compressor to come on. If it is, then you should verify continuity to the compressor. When they put your headers on, they could have unplugged the compressor wires.

 

I want to thank you guys for all the help, I finally fix the problem . I checked the wires for continuity, and led me to the broken/damaged compressor wire . It did cost me a little bit over $100 to check for leak (dye),evacuate and re-fill with fresh freon. I guess my A/C is good for another 10 yrs or so? Thanks again

 

Glad you fixed it, but just for future reference, you shouldn't be able to charge the car with Freon unless the ac clutch is working and turning on the compressor. The compressor is the only way to "suck" the refridgerant in, unless you put it under a vacuum. Even then you won't be able to fully charge it without the compressor running.

If someone told you they charged it with freon and the compressor wasn't running either:
a) they didn't know what they were doing
or
b) they lied

 

Well....he did tell me that he is going to put it under vacuum to see if it will take the charge. Thank you

 

I recently started the A/C in my 97 and it was blowing warm/hot air. I brought it to two separate dealers, one gave me a $1200 repair bill and another gave me a $1600 bill. They said that the compressor needed to be replace because it had a leak.

I hunting on the forum on how to recharge the system. Brought A/C testing gauges and did it per the book and advice given here. But it didn't fix the problem. I figured that the leak was going to cost me big dollars. Then I came across someone saying they tried Super Seal from inter-dynamics. I knew nothing else was wrong with the A/C system. The compressor worked, the clutch kicked in and out. The wires were OK and the head unit was fine. So I gave Super Seal a chance. Right now the A/C is blowing 39 degree air and has been for over two weeks. If it will hold for the summer, I'll have to see. But right now I didn't have to shell out the money and if a $20 can of stuff gets me through the summer I figure it a bonus at least for now. If it does hold, got to say I was a lucky one or this stuff is worth its weight in gold.

 

Hi, I've worked in the HVAC field for all kinds of applications in my younger days, commercial, houses, cars, and I can not figure why and how a qualified tech would evacuate and fill a systen without a compressor that will run. You should get your money back. I mean sure you could evacuate the system and then pump the proper measured amount back in, but why would you if you know the compressor won't run. There are better ways to test the compressor function then to fill it up that way.
Just my opinion
Good Luck