C 1500 Suburban 2WD V8-454 7.4L VIN N TBI (1995)
A/C Signal: Testing and Inspection
A/C Circuit
CIRCUIT AND TEST DESCRIPTION
Turning "ON" the air conditioning supplies CKT 59 battery voltage to the A/C compressor clutch and to terminal "E12" of the PCM connector to
increase and maintain idle speed.
The PCM does not control the A/C compressor clutch, therefore, if A/C does not function, refer to A/C diagnosis for diagnosis of the system.
If A/C is operating properly and idle speed dips too low when the A/C compressor turns "ON" or flares too high when the A/C compressor turns
"OFF," check for an open CKT 59 to the PCM. If circuits are OK, it is a faulty PCM connector terminal "E12" or PCM.
