a/c problem compressor works BUT?

Hello,
1999 GTP electonic climate control.
My a/c quit today. no codes. I checked the compressor clutch, it works if I jumper the relay contacts. The system has 95-100psi static pressure so it is not low on freon. When jumpered blows cool air. I checked the voltage coming to the clutch relay coil and get 14 volts on one side. This should pick the coil up, I swapped the horn relay and compressor still did not work. I suspect that the voltage I am seeing is a floating voltage and does not have enough current to pick up the clutch relay coil. I will see if it will light a test light tommorrow. I do not know where the switch is in the system that would say if there is low pressure. I found one switch that has 3 wires on it, is this it? usually low pressure switches only have 2. Any suggestions? anybody run into this before??? thanks for any help and your time.
Miked73USA :banghead:

the only switch on your car is on a line near the accumulator, and it is a three prong switch. Regretfully, my GM computer is for parts look-up only, and doesn't have any wiring diagrams.