A/C "on" Signal Diagnosis

A/C On Signal Diagnosis:

A/C "ON" SIGNAL DIAGNOSIS


CIRCUIT AND TEST DESCRIPTION:

Turning on the air conditioning supplies CKT 59 battery voltage to the A/C compressor clutch and to terminal "B8"of the PCM connector to increase idle air rate and maintain idle speed.

The PCM does not control the A/C compressor clutch, therefore, if A/C does not function, refer to HEATING VENTILATION AND AIR CONDITIONING 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 "B8" or PCM.