Toyota 1993 MR2 Wiring Diagrams page 175

3. OPERATION OF AIR INLET SERVO MOTOR
∗ SWITCHING FROM FRESH TO RECIRC
WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS FROM GAUGE FUSE TO TERMINAL 1 OF AIR INLET SERVO MOTOR.
WHEN THE RECIRC/FRESH SW IS SWITCHED TO THE RECIRC SIDE, THE CURRENT FLOWS FROM TERMINAL 4 OF AIR INLET SERVO
MOTOR TERMINAL 3
AND THE DAMPER MOVES TO THE RECIRC SIDE.
WHEN IT IS IN THE RECIRC POSITION, THE CURRENT IS CUT INSIDE THE SERVO MOTOR AND THE DAMPER STOPS AT THAT
POSITION.
∗ SWITCHING FROM RECIRC TO FRESH
WITH IGNITION SW ON, WHEN THE RECIRC/FRESH SW IS SWITCHED TO THE FRESH SIDE, THE CURRENT FLOWS FROM TERMINAL
4 OF AIR INLET SERVO MOTOR
THE MOTOR ROTATES AND THE DAMPER MOVES TO THE FRESH SIDE.
WHEN IT IS IN THE FRESH POSITION, THE CURRENT IS CUT INSIDE THE SERVO MOTOR AND THE DAMPER STOPS AT THAT
POSITION.
4. OPERATION OF AIR VENT MODE CONTROL SERVO MOTOR
WITH IGNITION SW TURNED ON, THE CURRENT FLOWS FROM GAUGE FUSE TO TERMINAL 6 OF AIR VENT MODE CONTROL SERVO
MOTOR TERMINAL 7 GROUND, AND THE DAMPER MOVES TO THE POSITION OF THE MODE SELECTION SW OF THE CONTROL
ASSEMBLY SW.
WHEN THE MODE SELECTION SW OF A/C CONTROL ASSEMBLY IS MOVED TO DEF POSITION WITH THE DAMPER IN THE FACE
POSITION, THE CURRENT FLOWS FROM TERMINAL 5 OF AIR VENT MODE CONTROL SERVO MOTOR TO TERMINAL (C) 14 OF A/C
CONTROL ASSEMBLY TERMINAL (C) 15
AS A RESULT, THE SERVO MOTOR OPERATES UNIT THE DAMPER REACHES DEF POSITION.
FOOT/DEF POSITION: THE CURRENT FLOWS FROM TERMINAL 4 OF SERVO MOTOR TO TERMINAL (C) 5 OF A/C CONTROL
ASSEMBLY.
FOOT POSITION: THE CURRENT FLOWS FROM TERMINAL 3 OF SERVO MOTOR TO TERMINAL (C) 4 OF A/C CONTROL ASSEMBLY.
BI–LEVEL POSITION: THE CURRENT FLOWS FROM TERMINAL 2 OF SERVO MOTOR TO TERMINAL (C) 13 OF CONTROL ASSEMBLY.
5. AIR CONDITIONER OPERATION
THE A/C AMPLIFIER RECEIVES VARIOUS SIGNALS, THE ENGINE SPEED SIGNAL FROM THE IGNITER, OUTLET TEMPERATURE
SIGNAL FROM THE A/C THERMISTOR AND CURRENT TEMPARATURE FROM THE WATER TEMP. SW, ETC.
WHEN THE ENGINE IS STARTED AND THE A/C SW (A/C CONTROL ASSEMBLY) IS TURNED ON, THE CURRENT FLOWS FROM A/C
FUSE TO TERMINAL (B) 5 OF A/C CONTROL ASSEMBLY
AT THIS TIME, THE A/C AMPLIFIER IS ACTIVATED AND CURRENT APPLIED FROM A/C FUSE TO TERMINAL 1 OF A/C MAGNETIC
CLUTCH RELAY FLOWS FROM TERMINAL 3 OF A/C MAGNETIC CLUTCH RELAY
GROUND. THIS CAUSES THE A/C MAGNETIC CLUTCH RELAY TO TURN ON, SO CURRENT APPLIED TO TERMINAL 2 OF A/C
MAGNETIC CLUTCH RELAY FLOWS FROM TERMINAL 4 OF A/C MAGNETIC CLUTCH RELAY
CLUTCH GROUND, CAUSING THE A/C COMPRESSOR TO OPERATE.
WITH THE ACTIVATION OF A/C AMPLIFIER, CURRENT APPLIED FROM A/C FUSE TO TERMINAL 2 OF VSV (FOR A/C IDLE–UP) FLOWS
FROM TERMINAL 1 OF VSV (FOR A/C IDLE–UP)
VSV TO AVOID LOWERING THE ENGINE SPEED DURING AIR CONDITIONER OPERATION.
WHEN ANY OF THE FOLLOWING SIGNALS ARE INPUT TO THE A/C AMPLIFIER, THE AMPLIFIER OPERATES TO TURN OFF THE AIR
CONDITIONER.
∗ THE ENGINE SPEED DECREASES. (3S–GTE)
∗ COOLANT TEMP. SIGNAL IS HIGH.
∗ A SIGNAL THAT THE TEMPERATURE AT THE AIR OUTLET IS LOW.
∗ A SIGNAL THAT THE REFRIGERANT PRESSURE IS ABNORMALLY HIGH OR LOW.
TERMINAL (C) 1 OF A/C CONTROL ASSEMBLY
TERMINAL 1 TERMINAL (C) 9 OF A/C CONTROL ASSEMBLY
GROUND.
TERMINAL 14 OF A/C AMPLIFIER
TERMINAL (C) 15
TERMINAL (B) 6 TERMINAL 11 OF A/C AMPLIFIER.
TERMINAL 15 OF A/C AMPLIFIER
TERMINAL 6
GROUND, THE MOTOR ROTATES
TERMINAL (C) 15 GROUND,
TERMINAL 6
TERMINAL 1 OF A/C MAGNETIC
GROUND, AND TURNS ON THE
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