Toyota ST185 Series Repair Manual page 151

RADIATOR FAN AND AIR CONDITIONER (AUTOMATIC AIR CONDITIONER, FOR PUSH TYPE OF BLOWER CONTROL SW)
SYSTEM OUTLINE
1. COOLING FAN OPERATION
WHEN THE IGNITION SW IS TURNED ON, THE CURRENT FROM IGN FUSE FLOWS TO TERMINAL 3 OF RADIATOR FAN RELAY NO. 1
TERMINAL 4 TERMINAL 3 OF THE A/C PRESSURE SW
TERMINAL 2 (5S–FE)
SW TERMINAL 2 TERMINAL 1 OF WATER TEMP. SW (FOR FANS CONTROL)
RELAY NO. 1 AND RELAY NO. 2 OF EACH FAN TO TURN ON.
* OPERATION AT LOW SPEED
WHEN THE A/C SW (A/C CONTROL ASSEMBLY) IS TURNED ON AND THE AIR CONDITIONER OPERATES, THE CURRENT FLOWS
FROM GAUGE FUSE FLOWS TO TERMINAL 2 OF A/C MAGNET CLUTCH RELAY
CAUSING A/C MAGNET CLUTCH RELAY TO TURN ON.
AT THAT TIME, THE CURRENT FROM GAUGE FUSE FLOWS TO TERMINAL 4 OF A/C MAGNET CLUTCH RELAY
TERMINAL 4 OF A/C MAGNET CLUTCH
FAN RELAY NO. 3 TERMINAL 3
AS A RESULT, A/C MAGNET CLUTCH AND A/C FAN RELAY NO. 3 TURN ON AND THE CURRENT FLOWS FROM FL CDS FAN
TERMINAL 2 OF A/C CONDENSER FAN MOTOR
1 OF A/C FAN RELAY NO. 2
TO EACH FAN MOTOR IN SERIES, CAUSING THE COOLING FAN TO ROTATE AT LOW SPEED.
* OPERATION AT HIGH SPEED
DURING A/C OPERATION, WHEN THE PRESSURE OF A/C COMPRESSOR BECOMES HIGHER THAN NORMAL PRESSURE (MORE
2
THAN 14.3 KG/CM 1401 KPA, 203 PSI), THE A/C PRESSURE SW TURNS OFF.
AS A RESULT, FAN RELAY NO. 1 AND NO. 2 TURNS OFF AND THE CURRENT FLOWS FROM FL RDI FAN
FAN RELAY NO. 1 TERMINAL 2
TERMINAL 2 OF A/C CONDENSER FAN MOTOR
1 OF A/C FAN RELAY NO. 2
ROTATE AT HIGH SPEED. WHEN THE ENGINE COOLANT TEMPERATURE BECOMES MORE THAN ABOUT 90°C (194° F), THE WATER
TEMP. SW TURNS OFF AND THE SAME OPERATION AS ABOVE IS PERFORMED.
2. HEATER BLOWER MOTOR OPERATION (PUSH TYPE BLOWER CONTROL SW (W/ AUTO A/C)
CURRENT IS APPLIED AT ALL TIMES THROUGH THE HEATER FUSE TO TERMINAL 5 OF HEATER RELAY. WHEN THE IGNITION SW IS
TURNED ON, CURRENT FLOWS THROUGH GAUGE FUSE TO TERMINAL 3 OF HEATER RELAY
A/C AUTO AMPLIFIER. AT THE SAME TIME, CURRENT ALSO FLOWS FROM GAUGE FUSE TO TERMINAL 5 OF A/C BLOWER CONTROL
RELAY TERMINAL 7
* LOW SPEED OPERATION (OPERATION AT MANUAL)
WHEN THE BLOWER SW (A/C CONTROL ASSEMBLY) IS MOVED TO LOW POSITION, SIGNALS ARE INPUT FROM TERMINAL C3 OF
THE A/C CONTROL ASSEMBLY, TERMINAL BSW OF THE A/C AUTO AMPLIFIER AND TERMINAL B4 OF THE A/C AUTO AMPLIFIER AND
TERMINAL B4 OF THE A/C CONTROL ASSEMBLY TO TERMINAL 10 OF THE A/C AUTO AMPLIFIER, CAUSING THE A/C AUTO
AMPLIFIER TO OPERATE.
CURRENT FLOWING TO TERMINAL HR OF A/C AUTO AMPLIFIER FLOWS TO TERMINAL GND OF A/C AUTO AMPLIFIER
AND TURNS THE HEATER RELAY ON.
THIS CAUSES THE CURRENT TO TERMINAL 5 OF THE HEATER RELAY TO FLOW TO TERMINAL 4 OF HEATER RELAY
OF BLOWER MOTOR MOTOR
BLOWER MOTOR TO ROTATE AT LOW SPEED.
* HIGH SPEED OPERATION (OPERATION AT MANUAL)
WHEN THE BLOWER SW (A/C CONTROL ASSEMBLY) IS MOVED TO HI POSITION, SIGNALS ARE INPUT FROM TERMINAL C3 OF A/C
CONTROL ASSEMBLY, TERMINAL BSW OF A/C AUTO AMPLIFIER AND TERMINAL B9 OF A/C CONTROL ASSEMBLY TO TERMINAL HI
OF A/C AUTO AMPLIFIER, CAUSING THE A/C AUTO AMPLIFIER TO OPERATE.
CURRENT TO TERMINAL HR OF THE AUTO AMPLIFIER THEN FLOWS TO TERMINAL GND OF A/C AUTO AMPLIFIER
TURNING THE HEATER RELAY ON.
AT THE SAME TIME, CURRENT FLOWING TO TERMINAL 5 OF THE A/C RELAY BOX FLOWS TO TERMINAL 7 OF A/C RELAY BOX
TERMINAL FR OF A/C AUTO AMPLIFIER
SPEED.
154
GROUND, FROM TERMINAL 2 OF A/C FAN RELAY NO. 2
GROUND, AND FROM TERMINAL 1 OF A/C MAGNET CLUTCH RELAY
GROUND.
TERMINAL 1
TERMINAL 5 TERMINAL 2 OF A/C CONDENSER FAN MOTOR
TERMINAL 2 OF RADIATOR FAN MOTOR
TERMINAL 1
TERMINAL 3 GROUND, FLOWING TO EACH FAN MOTOR IN PARALLEL CAUSING THE COOLING FAN TO
TERMINAL FR OF A/C AUTO AMPLIFIER.
TERMINAL 1 TERMINAL 1 OF BLOWER RESISTOR
TERMINAL GND
TERMINAL 2 TERMINAL 1 OF WATER TEMP. SW (FOR FANS CONTROL)
TERMINAL 4
TERMINAL 2 (5S–FE)
TERMINAL 3
TERMINAL 4 OF A/C FAN RELAY NO. 3
TERMINAL 1
TERMINAL 4 OF A/C FAN RELAY NO. 3
GROUND, CAUSING THE BLOWER MOTOR TO ROTATE AT HIGH
TERMINAL 3 OF A/C PRESSURE
GROUND, CAUSING
TERMINAL 8 OF A/C AMPLIFIER
TERMINAL 1
TERMINAL 2 OF A/C
TERMINAL 1
TERMINAL 1 GROUND, FLOWING
TERMINAL 1 OF RADIATOR
GROUND, AND FROM FL CDS FAN
TERMINAL 1
TERMINAL 1 TERMINAL HR OF
TERMINAL 4 GROUND, CAUSING THE
TERMINAL
TERMINAL
GROUND
TERMINAL 2
GROUND,