07 Volvo 670 Ac compressor problem

Yes. It stops when I turn the A.C. off, works normal will engage when coolant temp rises over 210degrees.
How does the A.C. system know when needs extra air , more than road rolling flow through condenser , and engage the fan? Is the sensor on the passenger side under the windshield controlling the fan?

 

no its a low or high pressure switch that ties into making the fan come on

 

The whole goal of engaging the fan is to control the A/C system high side pressure. High pressure means there isn't enough heat being pulled out of the condensor.

 

Bingo∆∆∆