Rear Auxiliary Ventilation Controls

The Rear Auxiliary Air Delivery and Temperature Controls provided with the combined Rear Auxiliary Heater and Air Conditioner option (C36 + C69) work independently of the ventilation controls used for the front of the vehicle. The front system is provided with a Recirculation Door and door controls but the rear auxiliary system does not have this capability. The Rear Auxiliary Mode Door and the Rear Auxiliary Temperature Door are exclusively controlled from either of two Auxiliary HVAC Control Modules. The Front Auxiliary HVAC Control Module's Blower Switch, located above the IP, has a permissive position (REAR) which enables control from the Rear Auxiliary HVAC Control Module. In the REAR position, if the Ignition Switch is in RUN, relay contacts in the Auxiliary HVAC Control Logic Module change state to enable control input from the ventilation controls at the Rear Auxiliary HVAC Control Module. When the Front Auxiliary HVAC Control Module's Blower Switch is not in the REAR position, the logic module's relay is deenergized and controls inputs from the Front Auxiliary HVAC Control Module controls the doors.

Each control module produces a variable voltage signal to the door motor. Each door motor 15 powered from the BRN (341) wires when the Ignition Switch is in the RUN position. Door grounding is through the BLK (150) wires to Ground G400. The variable voltage signal causes the door motor to operate to a position consistent with the signal's voltage. The voltage corresponds to the control dial selection on the selected control module.