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A/C Signal: Description and Operation

A/C IDLE-UP SIGNAL

DESCRIPTION
The A/C Idle-Up Signal is sent from the A/C amplifier. When the A/C compressor clutch is energized, the A/C amplifier will pull a signal low that is in series with the A/C Solenoid Vacuum (SV) valve. The Engine Control Module (ECM) uses this signal to adjust the air/fuel mixture for the lean condition the A/C SV valve creates. The vehicle's engine speed will be increased slightly to prevent stalling.