Subaru SVX 1992 Manual page 957

AUTOMATIC AIR CONDITIONING SYSTEM [M40181 4-7
18 . AIR MIX DOOR MOTOR
The air mix door motor is installed on the bottom
surface of the heater unit. When it receives a signal from
the auto amplifier, it changes the opening of the air mix
door via a link and the air mix door lever.
The door motor detects the air mix door position. P.B.R .
is built into the motor, and its signal is fed back to the
auto amplifier .
Fig. 57
1) Operation of air mix door motor
The auto amplifier determines the air mix door position.
The air mix door motor rotates normally or in reverse
direction corresponding to the auto amplifier signal as
shown below.
The output shaft and sliding contact are made integral .
If the sliding contact exceeds the position of terminal
plate ® or ® (MAX-HOT or MAX-COLD position), the
current is cut off and the motor stops rotating .
If the auto amplifier output signal turns OFF, the motor
operation stops irrespective of the position of the slid-
ing contact .
Energizing terminal
Direction of
Positive ~+ Negative Q
rotation
Remarks
1@ ©
CCw
MAX HOT -~
MAX COLD
©
(D
CW MAX COLD ->
MAX HOT
P.B .R . O 3
Terminal 2
plate Al~
6
Auto
amp.
Max hot
Max cold
3
2 1 1 1
Terminal plate ©
7 6 5 4
C4-419
Fig. 58
2) P .B .R . (Potentiometric Balance Resister)
The potentiometric balance resister is built into the
printed board in the air mix door motor. This resister
detects the air mix door position corresponding to the
output shaft rotation as a ratio of variable terminal
voltage VM to reference voltage VDD, and feeds the
signal back to the auto amplifier .
Max Max
ho~~`cold
0.9
Ratio
VM
VDD
5 3
4
vM
0.1
VDD
0
Max
Max.
hot
Air mix door position cold
04-420
Fig . 59
23