249
1. AIR INLET CONTROL SERVO MOTOR OPERATION (FOR PUSH SW TYPE)
(SWITCHING FROM FRESH TO RECIRC)
WITH THE IGNITION SW ON, CURRENT FROM THE GAUGE FUSE FLOWS TO TERMINAL 1 OF THE SERVO MOTOR. WHEN THE
RECIRC SW IS TURNED ON, THE CURRENT FLOWS FROM SERVO MOTOR → TERMINAL 3 → TERMINAL 5 OF THE HEATER
CONTROL SW → TERMINAL 1 → GROUND, THE MOTOR ROTATES AND THE DAMPER MOVES TO THE RECIRC SIDE. WHEN IT IS IN
THE RECIRC POSITION, THE CIRCUIT IS CUT INSIDE THE SERVO MOTOR AND THE DAMPER STOPS IN THAT POSITION.
WHEN THE CIRCUIT FOR THE INDICATOR LIGHT, CURRENT FLOWS FROM THE GAUGE FUSE → TERMINAL 12 OF THE HEATER
CONTROL SW → INDICATOR LIGHT → TERMINAL 1 → GROUND AND THE INDICATOR LIGHT CONTINUES TO LIGHT UP WHILE THE
RECIRC SW IS ON.
(SWITCHING FROM RECIRC TO FRESH)
WHEN THE IGNITION IS ON AND THE FRESH SW IS TURNED ON, CURRENT FLOWS FROM TERMINAL 2 OF THE SERVO MOTOR →
TERMINAL 6 OF THE HEATER CONTROL SW → TERMINAL 1 → GROUND, THE MOTOR ROTATES AND THE DAMPER MOVES TO THE
FRESH SIDE. WHEN THE DAMPER IS IN THE FRESH POSITION, THE CIRCUIT IS CUT INSIDE THE SERVO MOTOR AND THE DAMPER
STOPS IN THAT POSITION.
2. OPERATION OF AIR VENT MODE CONTROL SERVO MOTOR
WHEN THE IGNITION SW ON, CURRENT FLOWS FROM THE GAUGE FUSE TO TERMINAL 12 OF THE HEATER CONTROL SW,
TERMINAL 6 OF THE AIR VENT MODE CONTROL SERVO MOTOR.
WHEN THE DAMPER IS IN FACE POSITION AND THE BI–LEVEL OF THE HEATER CONTROL SW IS THEN TURNED ON, CURRENT
FLOWS FROM TERMINAL 3 OF THE HEATER CONTROL SW → TERMINAL 4 OF THE AIR VENT MODE CONTROL SERVO MOTOR SO
THAT A SINGAL THAT THE GROUND CIRCUIT IS ACTIVATED IS INPUT TO TERMINAL “B” OF THE CONTROL CIRCUIT INSIDE THE AIR
VENT MODE CONTROL SERVO MOTOR.
SIMULTANEOUSLY, A SIGNAL THAT THE GROUND CIRCUIT IS NOT ACTIVATED IS INPUT TO TERMINAL “A” OF THE CONTROL
CIRCUIT INSIDE THE SERVO MOTOR. THESE TWO SIGNALS ACTIVATE THE CONTROL CIRCUIT SO THAT CURRENT FROM THE
GAUGE FUSE TO THE SERVO MOTOR, CAUSING THE SERVO MOTOR TO OPERATE AND THE DAMPER TO MOVE TO BI–LEVEL
POSITION. WHEN THE DAMPER REACHES BI–LEVEL POSITION, A GROUND CUT SIGNAL IS INPUT TO TERMINAL “B” OF THE
CONTROL CIRCUIT, THE CONTROL CIRCUIT OPERATES, THE SERVO MOTOR STOPS ROTATING AND THE DAMPER STOPS AT
BI–LEVEL.
WHEN ANOTHER MODE POSITION IS SWITCHED TO, INPUT OF SIGNALS TO TERMINAL “A” AND TERMINAL “B” OF THE CONTROL
CIRCUIT THAT GROUND IS MADE OR GROUND IS NOT MADE (AS EXPLAINED ABOVE) ACTIAVTES THE CONTROL CIRCUIT AND
MOVES THE SERVO MOTOR TO THE DESIRED POSITION.
3. AIR CONDITIONING OPERATION
WHEN THE IGNITION SW ON, CURRENT FLOWS FROM GAUGE FUSE TO TERMINAL 12 OF THE HEATER CONTROL SW, TERMINAL 6
OF THE AIR VENT MODE CONTROL SERVO MOTOR.
WHEN THE BLOWER SW IS ON, CURRENT FLOWS FROM THE GAUGE FUSE → HEATER RELAY (COIL SIDE) → TERMINAL 7 OF THE
BLOWER SW → TERMINAL 5 → GROUND, ACTIVATING THE HEATER RELAY. THIS CAUSES CURRENT TO FLOW FROM THE HEATER
FUSE TO THE HEATER RELAY (POINT SIDE) → A/C FUSE → TERMINAL 7 OF THE HEATER CONTROL SW (A/C SW). IF THE HEATER
CONTROL (A/C SW) IS THEN TURNED ON AT THIS TIME, A SIGNAL IS INPUT TO THE A/C AMPLIFIRE. THIS ACTIVATES THE A/C
AMPLIFIER AND A/C MAGNETIC CLUTCH RELAY SO THAT CURRENT FLOWS FROM THE GAUGE FUSE TO THE A/C MAGNETIC
CLUTCH RELAY (POINT SIDE) → A/C MAGNETIC CLUTCH, CAUSING THE COMPRESSOR TO OPERATE. THE VSV (FOR A/C IDLE–UP)
IS TURNED ON SIMULTANEOUSLY TO PREVENT A DECREASE IN ENGINE SPEED DUE TO A/C OPERATION.
HEATER RELAY
(4)5– (4)4 : CLOSED WITH THE IGNITION SW ON AND BLOWER SW ON
A/C MAGNETIC CLUTCH RELAY
(4)5– (4)3 : CLOSED WITH THE IGNITION SW ON AND BLOWER SW ON AND A/C SW ON
A 2 A/C DUAL PRESSURE SW
1–4 : OPEN WITH PRESSURE 2.1 KG/CM (30 PSI, 206 KPA) OR ABOVE 27 KG/CM (384 PSI, 2646 KPA)
B 5 BLOWER RESISTOR
6–2 : APPROX. 1.12 Ω
2–3 : APPROX. 0.5 Ω
3–1 : APPROX. 0.2 Ω
SYSTEM OUTLINE
SERVICE HINTS