Recirculation Mode

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

When mode control switch is depressed, a signal is sent from the HVAC control head to the Instrument Panel Module (IPM), and to the recirculation actuator. The recirculation actuator moves into the recirculation mode when the IPM receives the signal. This circulates air from inside the vehicle instead of outside. Power is supplied when ignition is on. Ground is provided by the IPM. The recirculation actuator is equipped with feedback potentiometers. When the actuator receives 5 volts, the actuator moves in one direction. When the actuator receives zero volts it moves in the opposite direction. When the actuator receives 2.5 volts, actuator rotation stops. A reference signal is sent out from the IPM, to the recirculation actuator.

When a manual recirculation setting is selected, a separate reference signal is sent from the IPM. Reference voltage is used by the IPM to determine the position of the recirculation actuators. Recirculation mode can be used for both automatic and manual operation. Recirculation mode is not available when front defrost or vent is selected. Recirculation button will flash when recirculation mode is not available. When manually selected, recirculation will stay on until vent is selected or the recirculation mode has been on for about 10 minutes. Recirculation will come on automatically when maximum cooling is required in the automatic mode. When the HVAC system is off, pressing the recirculation switch will set the blower, mode and A/C compressor clutch in automatic mode.