Cadillac Repair: 99 Deville ac, ref ac, vacuum pump

Question
i have a 99 deville and i have a message on my dash that says low ref ac off    i had this checked out by a local shop they told me the compressor was bad  im not sure because i lack trust in this shop  but is this most likely a compressor issue if so where can i find details on how to change the compressor myself the wanted to charge an arm and a leg to do this  im the hands on type and would like to try this myself all i need is some direction

Answer
To do it your self you would need a:

Flush out the system with special equipment.
set of A/C gages.
a vacuum pump.
Ability to replace the orifice tube.
the correct amount of refrigerant oil to add to the system.
The correct amount of freon to add to the system.

tom