AC problem

I know its early for this sort of trouble but i want to get a head start on this repair if need be. My 2000 Grand Prix GT only gets cold AC on the passenger side two vents. I have the electronic dual zone climate control. It gets ICE cold on the passenger side, but just runs regular vent air on the driver side (center vent and two on driver side). I put a 12oz can of R134a in, but no change at all. The pressure at the low side is 25lbs and ambient temp today was 55 degrees F. The low side pressure was the same before and after the can of charge was added.

The heat comes out hot on both sides when i tell it to, and the dual zone will change the passenger side from hot to cold independant of the driver like it should. The only thing that doesn't work is AC on the drivers side. Where do i start troubleshooting this? I don't think its the R134a level as it really is ICE cold on the passenger side. Since i get hot and vent on driver side, makes me think its not a blend door either unless there is a special door just for AC. Please let me know, thanks!

not sure but I have read problems like this are sometimes caused by low refrigerant levels.

One question because I know it will help fellow forum members with better knowlegde of this problem....

Does yours a dual climat control, or is it just a standard dual climat control?

I have the dual zone automatic electronic climate control. I've read of others with this problem though they only had heat on the drivers side. I get outside ambient temp. vent air or heat or anywhere in between, just not cold AC. The passenger side vents get so cold with the AC on it will numb your hand in less than a minute. Should i continue to add refridgerant even though the passenger side is soo cold? I got into the diagnostic mode but there were no stored DTCs....

I would guess that your temp actuator for the drivers side is either bad, or the door it controls is blocked with debris. The other possibility is that the upper half of the AC evaporator core is blocked with debris or mildew and will not allow cold air to the drivers side.

The number one cause of A/C failure is loss of refrigerant due to a leak-- the way the evaporators are designed- the first cooled path into the evap is the air that gets directed to the passenger side- so if the charge is low or half- then the passenger side will cool fine- the driver's side will not-- with a full system charge, the a/c will now cool the driver's side-- Your sydtem holds about 36 ounces- if you added just one can you are about 1/2 or so of the way there- go ahead and add another- you should always be watching the high side- with a gage set - so as not to overcharge it-- Your Variable stroke V-5 compressor will control the suction side to be between 25 and 30 psi at all times- for optimum cooling- it does not cycle by design- it is a variable compressor- look for a leak around the front clutch area of the compressor- these are known for shaft seal leaks- there will be an oil sling on anything near the compressor- like th eradiator hose etc-- if so- there is your leak-- the seal can be replaced if you can find someone who has done them before....

So then can I rule out the blend doors, since i can get heat and regular (non heat) on the driver side? I don't have a manifold set, but will have to pick one up in the next month or so as it begins to warm up. There is a white dried powdery sling spray mark on the under hood liner in line with the belts and a little more back by the firewall. I can also smell the sour regridgerant smell in the car with the heat on. I bought some AC stop leak 2 step thing with one small can for metal leaks and one for rubber leaks but have not put it in yet until i determined if it was in fact low or was an electrical/mechanical failure.

Stop leak is a NO NO....It does not work--I would never try it unless I am never going to service it again-- It is the A/C mechanic's worst nightmare because it plugs up the machine that attaches to your car to service it-- I have photos of hardend plugged hoses.....

The best thing to do is fix your leak- once it is clearly defined- about 90% of the time on your vehicle the leak is at the compressor shaft seal-- if you want to better define it-- then use some refrigerant that has the flourescent dye in it-- NOT the stop leak......I can fix those in my sleep- usually do over a hundred every year.......

I was shying away from low refrigerant levels because you said the pass side blew so cold, but with the additional info you gave, it's definitely low R134a due to the leak you found. I agree with brcidd that A/C stop leak is a bad idea.

Thanks for all the great info! It really is a leak, I now have no cold ac on either side. For an hour or so the driver side got colder, but still not as cold as the passenger side. Yesterday it hit 60 so i tried the AC again, both sides blowing vent temp air, no cold air. I'm going to get some of that r134a with dye in it to try and trace down the problem. If its the pump shaft seal, how much would that cost to replace, or do most places just want to replace the compressor? I notice the compressor is louder now then when it had more refridgerant in it that leaked out last week.

Most times you can R&R the pump shaft seal. Its not a very difficult job, but requires special tools to pull the pulley and bearing. It would still be cheaoer to pay a shop labor to replace a compressor shaft seal versus buying a new compressor, unless your compressor is shot.

Thats a good idea, buy refrigerant with die in it, and then when you take it to the shop to have the work done, they wont have any trouble finding the leak.

Good luck!