1004 2004 chevy Silverado, 2500HD. I;ve added Freon ad it reflects as full. Turn on AC, and it cycles on and off. Hooked up pressure gauge, starts at about 60, then drops to 15 pounds. Then switch turns off, keeps doing this over and over. Is the low pressure switch bad or is it something else.

 

I take it the 60 is the suction side. If you are having this experience watching the pressure with a gauge, and the low pressure switch is cutting out, not the switch IMO. Try adding more freon, how much did you add to the system to begin with?

 

I added about 1/2 a can. Gauge registers full.

Thanks