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Systems
Air Flow System
The purpose of the air flow system is to provide
air to the heating, ventilation, defroster, and air
conditioning systems.
Control of the air flow is accomplished by four
types of systems which are Subaru model specific:
➊ Manual cable - Justy
➋ Manual cable/vacuum -Loyale
➌ Manual cable/electric - Legacy,
Impreza, and XT
➍ Automatic electric - SVX
The mode selector controls the rout-
ing of air to the defroster, heater core, air
conditioning evaporator, and the outlet ducts. The temperature control
lever adjusts the temperature of the air admitted to the passenger compart-
ment and regulates the flow of air through the heater core via the air mix
doors. The fan switch controls the speed of the fan and thus the
volume of air that flows through the evaporator and heater cores.
Loyale vehicles have vent control levers which are not a part of the mode
selector switch. These are manually adjusted by the driver and passenger to
admit or restrict the flow of outside air through side vent outlets.
The Legacy and the Impreza have eight position mode panels while the
Loyale and XT have six button panels. The additional VENT mode supplies
outside air to the passenger compartment through the dash vents. The flow
of vent air may be increased by using the fan, and heated by increasing the
temperature control setting. The DEF/HEAT mode switches the A/C com-
pressor ON and supplies air flow to the defrost and floor outlets. The remaining
mode switches operate similar to other Subaru A/C system controls.
The air flow unit used on Legacy vehicles equipped with manual A/C
systems is similar to the unit used on Automatic Climate Control
equipped vehicles.
Loyale Vacuum System (Mode Control)
Only Loyale vehicles use a manually actuated vacuum operated system to
control the position of the mode and circulation shutter actuators.
The vacuum system operates the air flow shutters in all Loyale vehicles. Check
vacuum to the shutter actuators if the defroster, floor vents, or fresh air vents do
not operate properly. The vacuum system also provides vacuum to the FICD
diaphragm based upon FICD solenoid signal, if so equipped.
XT Mode Control System
In XT vehicles, the electrical mode control system operates the various mode
shutters and doors.
Electric motors control the operation of the air flow shutters in the XT. The
motors operate the shutter actuators through a gear drive and linkage assembly.
If the flow of air through the defroster, floor vents, or other vents is insufficient,
check operation of the shutter actuators and switches.
A/C Cut System
This system is installed on many 1987 and later model year automatic transaxle
equipped Subaru vehicles. The purpose of the A/C cut system is to improve
engine performance during full throttle acceleration. Refer to the chart to
determine component application for the various models listed.
Note: All sequential MFI equipped vehicles feature
A/C cut systems.
Components
Fuel
Model System Trans A/C A/C
Cut K/D K/D Cut
Unit SW. Relay Relay ECM TPS Map
XT / XT6 / ”L” MFI 4EAT
”L” MFI 3AT
TBI
Legacy SVX MFI ALL
Justy Impreza
Justy Carb ECVT
”L” / HB Carb 3AT
“L” Series Air Flow System Controls
Vent Switches
Legacy/Impreza Mode Panel
Electrical System Operation
A/C Cut System
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