2004 Envoy Stalling

this is a tough one , may need more info , there are several components it could be , do you hear any noise when you turn the switch from under the hood ,

we can try to narrow it down , try locating the ac compressor under the hood , there will be a plug on it , remove the plug and try the a/c defrost , s ee what happens , if its the same we will move on from there

my father has unplugged it and it still stalls, we let it run while he is under the hood and while the ac is on it sounds like the die is just going to die and then it idles high and then acts like it wants to die again. I took it to the shop yesterday and the guy told me it was because my freon was low so he added some more, and while it was sitting at the shop it did not do it. I left drove down the road with the ac on and it was fine but once I came to a stop light it started tostall out again. Also since this has been happening the ac nor heat will not blow from the front two vents it blows on the floor and the sides. I looked on line and I saw another envoy user was having the same problem and he said the 2004 envoy has a tsb for this problem. do you know anything about a tsb?

the only thing i see is a tsb for the ev fan clutch and a software update,i will keep digging and see what i find, is there any other problems inside , radio or anything else electronic?? while i try and figure this out you may want to try and find the pressure switch and unplug that and try it , look at the pass side firewall , find the ac lines , one will have a switch and plug on it ,the systems are designed to not have max pressure until the trottle postion is advanced , btw any lights on at all???
we also may be looking at possibly two different problems , im going to try and help but this one will be tough not being able to look at it

we unplugged the pressure switch yesterday and they did not do anything. All the other elctronics work fine, when I am on the highway the truck runs fine even with the ac on but as soon as I have to come to a stop that's when it starts stalling.