GMC Repair: 98 GMC Jimmy A/C, refrigerant pressure, gmc jimmy

Question
I have a 98 GMC Jimmy and the air conditioner will not work. The compressor is full of refrigerant but only hot air comes out. Two years ago I replaced the compressor and the blower motor and the A/c worked fine for two years. Last year at the end of summer it just went out. I checked the refrigerant pressure and it was empty so I refilled it but hot air still comes out. One of my friends said that the compressor is leaking from the low pressure valve. If this is the case, wouldnt it work for a short time when I refilled it? I'm trying to find the cheapest way to get this fixed. This car is money pit and have paid more to fix it than what I have paid for it.

Answer
Try taking the low pressure sensor plug off and jumping it with a paper clip. If the A/C works good then you have a bad switch and it should be replaced. If it does not work, then you should have it checked out by a professional to see if you do have a freon leak.