Auto Air Conditioning & Heater Repair: 1995 Chevy Silverado AC, chevy silverado, climate control

Question
The climate control  problem, blows cold strong air then changes to blowing warmer air and not as strong. Compressor and refrigerant levels check out normal. We suspect vacuum or electrical issue, which is more probable in a 95 Silverado? What should we check next?

Answer
See if you can answer some of these questions and I can help narrow down the problem..

1.  Does it start to blow cold again during the same drive cycle or do you have to shut it off
2.  Does the A/C light start to flash when the system stops working?
3.  How did you verify the system had the correct charge in it?
4.  Whent the system quits does the compressor continue to run, cycle or shut off?