[Hart_Rod]

I just want to follow up with the solution to my problem. I had my three wire pressure sensor after the orifice tube/expansion valve. I didn't think through this setup enough to realize that all the vintage air setups I have installed, have an expansion valve inside the cab and the OBS trucks have the orifice tube on the outlet of the condenser. I moved the sensor to the correct position and everything works perfectly now. Lesson learned. I draw my systems out now prior to ordering fittings or making lines.