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A/C Vacuum Switching Valve

When A/C is operated, ECM operates A/C Vacuum Switching Valve (VSV) to supply by-pass air to increase engine idle speed. A/C VSV is mounted on firewall, to right of ignition coil. See Fig 1 . No other information is available from manufacturer.

Fig 1: Identifying A/C VSV

Courtesy of GENERAL MOTORS CORP.