Yes, I know...long time no post.
I browse occasionally.
So I still have warm air out left three vents
And cold out of right two.
I did recharge, and that lasted couple days.
Whats next? Do I just take it in?
What should I be hearing from ac person as to cause?
Pricing of fix?
Thanks for help you great grand prix enthusiasts

Wish I could help ya with the dual-zone system, but I can't. Welcome back, though! Never mind about the question, btw. I got the answer I was needing.

Welcome back

I have another a/c related issue that I never really got a solid answer on either. Mine will be blowing fine and cold and then before you know it, it's like the air quits coming out of the vents. You can still hear the blower blowing and it sounds louder almost because it's being blocked but it causes the car to get hot and you'll start to sweat! It doesn't do it a lot but I wish I could get it figured out myself. I almost believe something is closing the vents causing the air to be stopped somewhere in the system.

A response that comes to mind but didn't really get a good understanding of what it was might be your problem too but it seems like there was some kind of thing in the dash on the passenger side with a bunch of vacuum hoses going to it and that could be causing a issue. I never did look or replace mine because I didn't know what the response was talking about?

@snowcrash: have you considered the heater core or air in your coolant system? My RWD L36 was behaving much the same, only in reverse, during the cold months. The heater would be working good, but it would get COLD in the cabin as the ECT showed like 235*+.

I'm having pretty much the same issue. I definitely don't have the answer but I may be able to shed some light on this.
First off: I have a 97 gt with dual zone climate control. On the passenger side behind the glove box is the vacuum control or heater/ac control solenoids. This has a lot of vacuum tubes coming off of it leading to three actuators, which are basically diaphragms. The one on the passenger side, just above the blower, controls the inside/outside air door. The other one on the right side of the center console behind the glove box controls the defrost vent. The last one, tucked up even further on the driver's side on the left side of the center console controls the bottom, front and defrost vents.
There are two blend door actuators, one on the passenger side next to the defrost actuator and the other on the driver's side next to the other "diaphragm" actuator.
I really have no idea how all these things could affect one another. The issue that I'm having right now is that on long car rides (2-3 hours) the vents would "close" or at least it would seem like that. The blower fan would continue to blow and I could hear it but nothing was coming out any of the vents. Now, in addition there is cold air blowing strongly out of the two passenger side vents and warm air almost "wafting" out of the three driver's side vents. I cleaned the ignition switch of all carbon build up and I have yet to check the pressure in the ac lines. Also, one more thing is the little man on the display blinks, sometimes a steady blink and other times kind of random.
Hopefully this helps some and also if anyone has any suggestions for me it would be much appreciated. I'm a couple of steps away from buying a new ignition stater switch.

So I checked the pressure on the ac lines and I got around 32 psi, and around 2500 rpm it would get down to 25 psi. So I added a little just for good measure to get it back to 35 psi.

Took the gp in.
Freon was low.
Still have issue, sometimes cold until car warms up.
Says either blend door, possibly electrical problem.
He said easy and temp fix way is to bypass heater lines hoping to keep the heat from entering the cabin.
I'll give that a try.
Otherwise the dash would probably be torn apart and lots of money to be handed out.

Took the car to Polar ice.
Refrigerant was low, which I expected.
It got cold but then the left three vents
got hot again.
So either electrical issue or blend door issue.
So he said I can try bypassing the heater hoses.
So I modified the car once again!!
I have nice cold a/c now.

So now you have to find out why the refrigerant is low.

Nope, haven't considered that, but I can check to see if the coolant has any air in it. The procedure for that is crank the car and let it get warm and open the bleeder isn't or do you do it when it is cold as I can't remember.

What would the heater core have to do with it though if it wasn't leaking?

I also have the dual climate control and this is exactly what my car is doing. Normally on long trips or a couple hours, the air will be blowing cold and then it is like the vents close up and stop allowing the air to come out and it will begin to get hot in the car! It seemed like when it first started, you could shut the air off or move the mode to where it was blowing out and it sometimes would fix it but now it doesn't.

So if my freon is low, this will cause the vents to maybe shut and keep the air from blowing cold?

What does bypassing the heater lines from going into the car do as I assume they are keeping the stuff from going through the heater core.

I just really need to try and diagnose this issue because it sucks not having air and then the damn passenger side window not working as it is about the 3rd one in it. When it's cold it will sometimes work but not on no hot day.

the core could be blocked or something.

the procedure is to let the engine get warm, with the housing opened up. when the tstat opens, let the coolant spray out in a constant jet, lock down the bleeder, drive off into the sunset.

Actually I think by passing the core like that just takes the heat out of the equation. So when things start acting up you don't get "hot" air.

heater core and evap do similar things. they heat or cool air. if your a/c is working right, the line leaving the evap should always be cold. if it is and car interior is not cold, than your airblend door is messed up. most GM cars use a small elec stepper motor to adjust blend door. they get screwed up. out of position and sometimes just die. some cars you can manually get under dash and lock door in position so air will blow cold. so blend door motor might be bad or computer/climate control that controls door position can also be bad.