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Home >> GMC >> 1993 >> Suburban 1/2 Ton 2WD V8-350 5.7L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> A/C Signal >> Testing and Inspection
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A/C Signal: Testing and Inspection

A/C Request Signal Circuit (PCM):






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 control module connector to increase and maintain idle speed.

The control module does not control the A/C compressor clutch, therefore, if A/C does not function, refer to the A/C section.

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 control module. If circuits are OK, it is a faulty control module connector terminal "E12" or PCM.