trying to fix my a/c-1997 gmc
 

When I hit the a/c button the air coming out is actually hotter than when its just on vent. I need to take it down and have the system checked out but I also noticed my controls dont seem to work right. It only blows on the upper vents and the defrost. If I select it to blow on my feet , nothing comes out from underneath. Could it just be bad controls or could it be something else? Dont know anything about a/c systems, where do I start?

Re: trying to fix my a/c-1997 gmc
 

It sounds like you two issues:

1. You have no freon in the system. Typically due to a leak, this should be checked by a shop who can pressurize the system and look for a leak. Could also be a bad compressor, condenser, or other part of the system.
2. There are actuators that move doors in the airbox to deflect air to the different vents. It sounds like one of those actuators is not working. I believe the vent deflector is above and just to the right of the accelerator pedal. There are also linkage parts up in there that will come apart sometimes (been there, done that) and that will cause the deflectors to not move enough to send the air elsewhere.

Re: trying to fix my a/c-1997 gmc
 

small update, was out messing with it today and had no power to the compressor. All fuses and relays are good. The compressor turned on when we jumpered it. Pretty sure its too low to power up so I`m going to have to take it somewhere that does a/c services and have them fill it and charge the line and check for leaks and pray that fixes it.

Re: trying to fix my a/c-1997 gmc
 

Big update. Took it to a shop this morning, no appointment and they got it right in. Passed the vacuum test so he did some poking around and found a broken wire for the compressor. Repaired the wire, charged the system and I now have A/C. He did put a dye in and told me to come back in 100 miles so he can check for leaks. Only cost me $126 not counting the $165 I paid the mobile mechanic I bought the truck from to look at it and he couldnt find anything wrong. Now I just need to get the vent selector to work right. put it on feet and it still comes out the top vents some but does go to feet and go ot defrost and it doesnt come out of the defrost very very much but I feel something. It`s been 90+ all week so I`m not worried about the defrost just yet but I`m glad to have a/c finally.