Safari Van AWD V6-262 4.3L VIN Z TBI (1991)
Air Door Actuator / Motor: Description and Operation
Front Air Conditioning Vacuum System
DESCRIPTION
The front manual air conditioning system uses vacuum to operate the air valves (doors) that control airflow through the air conditioning module and
the heater water bypass valve that controls the flow of coolant through the heater core of the air conditioning system.
OPERATION
Vacuum is supplied from the vacuum tank on the right front wheelhousing. Just ahead of the air conditioning control assembly in the instrument panel,
the vacuum supply line divides into two branches. One branch brings vacuum to the rotary selector valve that is operated by the mode lever of the
control assembly. The other branch provides vacuum to the heater water bypass valve in the engine compartment, adjacent to the blower housing. A
vacuum hose harness brings vacuum from the ports in the rotary selector valve to the vacuum actuators for the air valves of the air conditioning
system. All actuators except the heater-defroster actuator are two-position actuators controlled by one vacuum hose. The heater-defroster actuator is a
three-position actuator with two vacuum hoses. Application of vacuum or vented air to each actuator is determined by the operating mode selected by
setting the mode lever in the control assembly. The vacuum chart indicate the air outlets that operate in each mode selection, and the response of the
rotary selector valve and heater water bypass valve switch to each mode lever position.
NOTE: If equipped with an auxiliary heater, the vacuum supply hose also has a T-fitting to a hose that feeds vacuum to the auxiliary heater hot water
valve control system.
