Lumina V6-204 3.4L DOHC (1991)
Air Conditioning Switch: Description and Operation
A/C On Signal, Pressure Transducer And Clutch Control Relay
This signal indicates that the A/C control switch is turned "ON" and that the A/C pressure sensor is functioning properly. The ECM uses this signal to
adjust the idle speed, and on some models engages the A/C compressor clutch. If this signal is not available to the ECM, the A/C compressor will be
inoperative and a Code 66 will result.
