Mode Control Knob

The mode knob operates a rotary vacuum that routes engine vacuum to specific hoses in the vacuum harness. These hoses control vacuum actuators on the HVAC module. Each actuator operates a valve, a door-like hinge deflector, that routes airflow to the various outlets of the heater system.

The mode knob has the following positions:
^ MAX A/C
^ NORM A/C
^ BI-LEV A/C
^ VENT
^ HTR
^ BLEND
^ DEFROST