tmise

I am having issues with the climate control unit. When car is running the unit looks normal. Only thing that works on it is the front and rear defrosters. It won't do anything when I press either AUTO button. So in other words I can't get AC or HEAT to work only the defrosters. Before the front defroster would blow pretty darn hard since it comes on full blast when I press the front defroster button. Now when I do it it doesn't seem to be blowing as hard but does seem to pick up after driving down the road for a couple of minutes or so. Anybody have any idea what maybe going on with it? Thought I had heard somewhere if there isn't enough refrigerant in the system it would shut the unit down to prevent damage to the AC unit which would explain why when I press the AUTO buttons nothing happens. Everything was working fine and the AC was nice and cold, it just didn't work one day. Maybe someone knows of a place that rebuilds them?