Diagnostic Aids

If complaint was insufficient cooling, problem may be caused by inoperative cooling fan(s) or faulty A/C refrigerant fan request switch. Engine cooling fan(s) should turn on when A/C pressure exceeds a value to open switch, causing ECM to energize cooling fan relay(s). See CHART C-12 for cooling fan diagnosis. If fan operates correctly, ensure A/C system refrigerant charge is okay.

Fig 1: A/C Clutch Circuit Schematic (3.1L - Front A/C Only)

Courtesy of GENERAL MOTORS CORP.

Fig 2: A/C Clutch Circuit Flow Chart, (3.1L - Front A/C Only)

Courtesy of GENERAL MOTORS CORP.