There wasn’t much info on this sensor that I could find, before this, I tried everything short of replacing major ac components. I actually discovered this by accident. To prove that this was the culprit I ran the vehicle, turned on the ac with it plugged in, ac clutch would not engage, unplug sensor and it would engage and start to cool, plug back in, ac clutch disengage.I am uncertain if failure of this sensor interrupts the circuit or not (don't have electrical manual in front of me) but the sensor is essentially an 'Air Quality' sensor.
IF it detects smoke/smog/poor quality air it will switch the HVAC system from outside air (if already selected) to recirculate.