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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 31 (ENGINE CONTROLS - THEORY & OPERATION - 8.1L)COMPUTERIZED ENGINE CONTROLSINPUT DEVICESA/C ON/REQUEST SIGNAL
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6

A/C On/Request Signal

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION A/C On/Request Signal
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Suburban, and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The A/C system can be engaged by either pressing the A/C switch or during automatic operation. The HVAC control module sends a class 2 message to the PCM for A/C compressor engagement. The PCM will provide a ground for the A/C compressor relay enabling it to close its internal contacts to send battery voltage to the A/C compressor clutch coil. The A/C compressor diode will prevent a voltage spike, resulting from the collapse of the magnetic field of the coil, from entering the vehicle electrical system when the compressor is disengaged.

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