Rear Auxiliary Ventilation Controls

The rear auxiliary air delivery and the temperature controls provided with the combined rear auxiliary heater and air conditioner option, work independently of the ventilation controls used for the front of the vehicle. The front system provides a recirculation door and the door controls. The rear auxiliary system does not have the recirculation door and the door controls. The rear auxiliary mode door and the rear auxiliary temperature door are exclusively controlled from either of the 2 auxiliary HVAC control modules. The front auxiliary HVAC control module blower switch is located above the IP. The front auxiliary HVAC control module blower has a permissive position called REAR. The REAR position enables control from the rear auxiliary HVAC control module. Relay contacts in the auxiliary HVAC control logic module change state in order to enable control input from the ventilation controls when in the REAR position with the ignition switch in the RUN position. The ventilation controls are located at the rear auxiliary HVAC control module. The logic module relay is de-energized when the front auxiliary HVAC control module blower switch is NOT in the REAR position. The logic module relay controls inputs from the front auxiliary HVAC control module that control the doors.

Each control module produces a variable voltage signal to the door motor. Each door motor is powered from CKT 341 (BRN) when the ignition switch is in the RUN position. Door grounding passes through CKT 150 (BLK) to ground G400. The variable voltage signal operates the door motor to a position consistent with the signals voltage. The voltage corresponds to the control dial selection on the selected control module. CKT 454 (WHT) and CKT 1199 (DK BLU) carries variable voltage from the Auxiliary HVAC Control Logic Module to the Auxiliary Mode Door Motor and Auxiliary Temperature Door Motor respectively. These motors adjust position proportionately to the input voltage provided.