GMC Repair: 1994 GMC Sonoma 4.3L - air conditioner compessor clutch, gmc sonoma, freon

Question
My A/C wasn't cooling and I assumed it needed freon. However, when the engine is running with the A/C on, the electrically controlled clutch just constantly cycles on and off. It doesn't turn the compressor for but about a second before it cuts off then cuts back on in another second or two.
The guage on the A/C charging system says that it has adequate freon pressure. Is the clutch cycling on and off because it is too full, too low, or some other problem with the clutch? The clutch doesn't appear to be slipping just that it is getting an electrical signal to release from the compressor.  

Answer
What you need to do is put a set of guages on the system and see what both the high and low side pressures are while the A/C is running. That is the first step in diagnosing A/C systems, if you could get me that information I will be able to help you more.

The low side pressure should be 30-34psi and the high side should be between 175-350psi. If you don't have enough freon the low side will get too low, and if there is a restriction or an airflow problem with the condenser the high side will get too high.