Avoid a trip to the mechanic by trying to troubleshoot problems yourself in your Pontiac Grand Prix. Air conditioning problems are quite common, but can often be quite simple to diagnose and even fix.
Start the car and turn the air conditioning on. Allow the engine to run a few minutes so the air can cool. Check to make sure you have the proper buttons selected. This simple step may uncover the root of the problem.
See if the problem is as simple as a blown fuse. It is probably a blown fuse if the temperature controls on the dashboard seem to work correctly but have no effect on the air. Find the fuse box in a Pontiac Grand Prix inside the glove box. Locate a small bin on the right side of the glove box and open it. The fuse controlling AC will be in location 28.