Grand Prix V6-191 3.1L VIN M SFI (1998)
Vacuum Solenoid Valve HVAC: Description and Operation
The vacuum solenoid module converts electrical signals from the heater A/C control microprocessor into vacuum commands which position the mode,
A/C-defrost, and outside air valves in the air distributor. Vacuum is constantly applied to the module which distributes the vacuum to five
solenoid-controlled valves on the module. When the heater A/C control signals the module to change an air distributor valve position, the associated
solenoid energizes and vacuum is applied to the proper actuator.