Chart C-10, 3.8L, A/C Clutch CTRL CKT Diagnosis

The A/C relay is PCM controlled. It is commanded on to engage A/C clutch when an A/C request command is received from the BCM via serial data circuit No. 800. During cranking, PCM may command the A/C clutch to turn on without an A/C request to prevent A/C slugging.

1. If A/C compressor does not operate because PCM is not receiving an A/C request command from the PCM, refer to G - TESTS W/ CODES article in this section.
2. If A/C compressor is engaged when A/C request displays YES, the clutch and related control circuits are functioning properly. If any abnormal operation is present, diagnose A/C system.
   NOTE: Test numbers refer to test numbers on diagnostic charts.
3. Determines whether compressor is staying engaged due to faulty relay or circuit No. 762 is shorted to ground.

Fig 1: A/C Clutch Control, Schematic, 3.8L

Courtesy of GENERAL MOTORS CORP.

Fig 2: A/C Clutch Control, Flow Chart (1 of 2), 3.8L

Courtesy of GENERAL MOTORS CORP.

Fig 3: A/C Clutch Control, Flow Chart (2 of 2), 3.8L

Courtesy of GENERAL MOTORS CORP.