May be a bad low pressure switch. Put a jumper across the two contacts and see if the system will cycle. The other quick check measure the voltage on both sides of the switch with the negative lead touching chassis. Voltage on one side and not on the other and you have the source of the problem. Check the Pressure on the low side of the system with a gauge and to see if the pressure is falling. If the level is OK and still no voltage being passed along to the compressor would point to the switch being bad.

If you do not have any voltage after the first cycle, into the passengers side you go. The AC Switch with the knob is the center console has a micro switch and on the very top there is a metal tube that goes down through the dash to the pipe going into the condenser coils. It should be intact and making good contact with the tube. You can remove the knob, pry the face plate off, and there is a nut up in the recess of the face plate holding it in place. Make it a habit to remove that nut and push the knob shaft out of the face plate any time you go into that console, unless you do not mind digging in the black goo to replace it. If the thermostat is bad you will need to dig into the goo, suggest pulling the passengers seat and glove box to get more room. Take of the side of the console and follow the tube down. I used Zip Ties to hold the new one in place and it is working well. I pulled one out of a donor car. New ones are not that expensive online, have not checked with the local Euro house for prices. I actually used a DPDT switch for a year and manually cycled the unit every so ofter in place of the thermostat.

There is also a relay on the lower Right hand side of the console that sends the voltage out to switch and on the green wire to the low pressure switch and then on to the compressor. If the thermostat is sending the voltage out, then you can jumper across the relay and prove that is the problem. I do not have the pin outs on the relay connector. The shade tree in me goes down to PUP and gets another relay from a donor.

Sounds like the PO took a short cut to get around figuring out what was wrong.

Good Luck and hope this helps,

PT