Is the pressostat switch also known as the "low Pressure" switch? The low pressure switch on the line near the firewall on the passenger side seems to be working right. Meaning it's a closed circuit now.

There is another switch near the low pressure valve (near passenger side headlight). This switch has a 5volt power in and two lines out. I think that one line goes to the fan and the other goes to the compressor. The fan is switching on so I think that this one is functioning too.

I don't think that it is a gap issue - as when I bypass all of the sensors and provide voltage from the battery directly to the compressor everything works.

Do you know if there is a way to bench test the climate control unit (these seem to be pretty pricey)?

Also, do you know if there is any other switch or sensor between the climate control unit and the relay. I am positive that whatever "unit/control/sensor/etc" that provides a ground for the low side relay coil to "close" the switch to the compressor is not doing its job. I thought that this would be the climate control unit, but I can't find continuity between either of the low side relay terminals and ANY of the terminals that plug into the back of the climate control unit.