I have a 1996 cavalier and when I turn on the A/C or the heater I have to turn it on at full blast in order for it to blow out air. Anyone have any ideas as to what the problem might be?

maybe you need some freon? check the fan maybe its not working properly at low speeds

The most likely culprit is the resister module located in the heater blower box under the glove box. This module controls fan speed. I had one fail in a 95 Cavalier and I could only get teh fan to run on the highest setting. Pretty simole to replace. I think it ran about $28 for the part from a GM dealer.

bnobrega
Any idead on how to go by replacing the part? What am I looking for when and how should I go by removing the glove box? Thanks for any help!

The module looks like a circuit board with various circuit etches and no components. I think there were two hex screws attaching it to the heater box. If I remember, this thing had a cable harness and it looked like a harness connector screwed into the heater box. You do not see that it is a circuit board until you have it removed.

If you look around under the Glove box you will see the screws that attached the glove box to the dashboard. Remove these and pull out the glove box. Next look up under the dashboard and you will see the assembly. You will need the proper size nut driver to get this thing out. It is no more than 30 minutes of work total.

Does it sound like it is trying to force out air but no movement of air.
Could be a plugged evaporator. If the evap leaks freon the dirt from the air will plug it. Yours options are limited to replacing the evap or trying to clean with solvent and an undercoating gun with a long hose through the blower motor hole