System Outline

1. COOLING FAN OPERATION
When the Ignition SW is turned ON, the current from IGN Fuse flows to TERMINAL 3 of Cooling Fan Relay no.3 --> TERMINAL1 --> TERMINAL 1 of water temp. SW (for Cooling Fan --> TERMINAL 2 --> GROUND, from TERMINAL 1 of Cooling Fan Relay no.2 --> TERMINAL 2 --> TERMINAL 2 of water temp. SW (for Cooling Fan) --> TERMINAL 1 --> GROUND, and also from TERMINAL 2 of Cooling Fan Relay no.1 --> TERMINAL 2 --> TERMINAL 2 of A/C pressure SW (high pressure) --> TERMINAL 3 --> GROUND, causing Cooling Fan Relays no.1, 2 and 3 to turn ON. At that time, the current from FL RDI fan flows to TERMINAL 3 of Cooling Fan Relay no.2 and TERMINAL 1 of Cooling Fan Motor no.1 --> TERMINAL 1 --> TERMINAL 4 of Cooling Fan Relay no.3 --> TERMINAL 5 --> TERMINAL 3 of Cooling Fan Relay no.1.

* Operation at low speed
During A/C operation, when the pressure of A/C Compressor becomes higher more than 1323 kPa, 13.5 kg/cm2 192 psi) than normal pressure the A/C high pressure SW turns OFF. As a result, Cooling Fan Relay no.1 turns OFF and the current flows from FL RDI Fan --> TERMINAL 2 of Cooling Fan Motor no.1 --> TERMINAL 1 --> TERMINAL 4 of Cooling Fan Relay no.3 --> TERMINAL 5 --> TERMINAL 3 of Cooling Fan Relay no.1 --> TERMINAL 4 --> TERMINAL 2 of Cooling Fan Motor no.2 --> TERMINAL 1 --> GROUND, flowing to the Fan Motor in series, causing the Cooling Fan to rotate at low speed.

* Operation at high speed
When the engine coolant temperature becomes more than about 90°C (194°F), the water temp. SW turns OFF. As a result, Cooling Fan Relays no.2 and no.3 turn OFF, and current flows from FL RDI fan to TERMINAL 2 of Cooling Fan Motor no.1 --> TERMINAL 1 --> TERMINAL 4 of Cooling Fan Relay no.3 --> TERMINAL 2 --> GROUND. At the same time, current flows from FL RDI Fan to TERMINAL 3 of Cooling Fan Relay no.2 --> TERMINAL 4 --> TERMINAL 2 of Cooling Fan Motor no.2 --> TERMINAL 1 --> GROUND, the current flowing to the Fan Motor in parallel causing the Cooling Fan to rotate at high speed.

2. HEATER BLOWER MOTOR OPERATION
Current is applied at all times through FL Heater to TERMINAL 5 of Heater Relay. When the Ignition SW is turned ON, current flows through Heater Fuse to TERMINAL 3 of Heater Relay --> TERMINAL 1 --> TERMINAL HR of A/C Control Assembly. At the same time, current also flows from Heater Fuse to TERMINAL IG+ of A/C Control Assembly and --> TERMINAL 3 of extra high speed Relay --> TERMINAL 5 --> TERMINAL FR of A/C Control Assembly.

* Low speed operation
When the Blower SW (A/C Control Assembly) is moved to low speed position, the current to TERMINAL HR of A/C Control Assembly flows to TERMINAL GND of A/C Control Assembly --> GROUND and turns the Heater Relay ON. As a result, the current to TERMINAL 5 of Heater Relay flows to TERMINAL 4 of Relay --> TERMINAL 2 of Blower Motor --> TERMINAL 1 --> TERMINAL 1 of Blower Resistor --> TERMINAL 2 --> GROUND and causes the Blower Motor to rotate at low speed.

* High speed operation
When the Blower SW (A/C Control Assembly) is moved to HIGH SPEED position, the current to TERMINAL HR of A/C Control Assembly flows to TERMINAL GND of A/C Control Assembly --> GROUND and turns the Heater Relay ON. At the same time, the current to TERMINAL 3 of extra high speed Relay also flows to TERMINAL 5 of Relay --> TERMINAL FR of A/C Control Assembly --> TERMINAL GND --> GROUND and turns the extra high speed Relay ON. As a result, the current to TERMINAL 5 of Heater Relay flows to TERMINAL 4 --> TERMINAL 2 of Blower Motor --> TERMINAL 1 --> TERMINAL 1 of extra high speed Relay --> TERMINAL 2 --> GROUND without passing through the Blower resistor, causing the Blower Motor to rotate at high speed.

* Medium speed operation
When the Blower SW (A/C Control Assembly) is moved to MED position, the current to TERMINAL HR of A/C Control Assembly flows to TERMINAL GND --> GROUND and turns the Heater Relay ON. Then, the current to TERMINAL IG+ of A/C Control Assembly flows to TERMINAL BLW --> TERMINAL B-2 of Power Transistor --> TERMINAL A-1 --> GROUND.

As a result, the current to TERMINAL 5 of Heater Relay flows to TERMINAL 4 --> TERMINAL 2 of Blower Motor --> TERMINAL 1 --> TERMINAL A-2 of power transistor --> TERMINAL A-1 --> GROUND and Blower Motor is rotated at medium speed by the A/C Control Assembly controlling the current flow from TERMINAL B-2 of power transistor to TERMINAL A-1.

* Auto function
When the auto SW in Heater control SW (A/C Control Assembly) is selected, the current flow is the same for MED position, but the A/C Control Assembly decides the appropriate air flow volume according to the set temperature and the input signals from each Sensor. by controlling the current flow from TERMINAL BLW of the A/C Control Assembly to TERMINAL B-2 of power transistor --> TERMINAL A-1 --> GROUND, the A/C Control Assembly controls the Blower Motor steplessly.

3. OPERATION OF AIR INLET CONTROL SERVO MOTOR
(Switching from Fresh to RECIRC)
With Ignition SW turned ON, the current flows from Heater Fuse to TERMINAL IG+ of A/C Control Assembly. When the RECIRC/FRESH SW is switched to the RECIRC side, the current flows from TERMINAL IG+ of A/C Control Assembly --> TERMINAL MREC --> TERMINAL 5 of air inlet control Servo Motor --> TERMINAL 4 --> TERMINAL MFRS of A/C Control Assembly --> TERMINAL GND --> GROUND, the Motor rotates 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 IG+ of A/C Control Assembly --> TERMINAL MFRS --> TERMINAL 4 of air inlet control Servo Motor --> TERMINAL 5 --> TERMINAL MREC of A/C Control Assembly --> TERMINAL GND --> GROUND, 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 Heater 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 which is ON.

When the DEF SW of A/C Control Assembly is turned ON, with the Damper in the face position, a signal is input from TERMINAL 5 of Air Vent Mode Control Servo Motor to TERMINAL DEF of A/C Control Assembly. As a result, the Servo Motor operates until the Damper reaches DEF position. When this occurs the signal to the A/C Control Assembly is shut OFF and rotation of the Motor stops.

Switching to other modes is controlled by the Servo Motor according to the following signals.
1. FOOT/DEF position, a signal input from TERMINAL 4 of Servo Motor to TERMINAL F/D of A/C Control Assembly.
2. FOOT position, a signal input from TERMINAL 3 of Servo Motor to TERMINAL FOOT of A/C Control Assembly.

5. OPERATION OF AIR MIX CONTROL SERVO MOTOR
When the temperature control SW is pushed to the "cool" side, the current flows from TERMINAL MC of A/C Control Assembly --> TERMINAL 2 of air mix control Servo Motor --> Motor --> TERMINAL 6 --> TERMINAL MH of A/C Control Assembly --> GROUND and the Motor rotates. The Damper opening angle at this time is input from TERMINAL 4 of Servo Motor to TERMINAL TP of A/C Control Assembly, this is used to determine the DAMPER STOP position and maintain the set temperature.
When the temperature control SW is pushed to the "warm" side, the current flows from Servo Motor --> TERMINAL MH of A/C Control Assembly --> TERMINAL 6 of Air Mix Control Servo Motor --> Motor --> TERMINAL 2 --> TERMINAL MC of A/C Control Assembly, rotating the Motor in reverse and switching the Damper from "cool" to "warm" side.


6. AIR CONDITIONING OPERATION
The A/C Control Assembly receives various signals. i.e.. the engine rpm signal from the Igniter, outlet temperature signal from the A/C Thermistor, engine coolant temperature from the water temp. Sensor, and the lock signal from the A/C compressor, etc.
When the engine is started and the A/C SW (A/C Control Assembly) is turned ON, a signal is input to the ECU inside the A/C Control Assembly. As a result, the GROUND circuit in A/C Control Assembly is closed and current flows from Heater Fuse to TERMINAL 1 of Magnetic Clutch Relay --> TERMINAL 3 --> TERMINAL ACMG of Engine Control Module (Engine and Electronic Controlled Transmission ECU) --> TERMINAL GND --> GROUND, turning the Magnetic Clutch Relay ON, so that the Magnetic Clutch is ON and the A/C compressor operates.
At the same time, the Engine Control Module (Engine and Electronic Controlled Transmission ECU) detects the Magnetic Clutch operating and rotates the idle air control (ISC) step Motor in the open direction to avoid lowering the engine rpm during air conditioning operation.
When any of the following signals are input to the A/C Control Assembly, the Control Assembly operates to turn OFF the air conditioning.

* Engine high rpm signal
* Engine coolant high temp. signal is high.
* A signal that the temperature at the air outlet is low.
* A signal that there is a large difference between Engine rpm and Compressor rpm.
* A signal that the refrigerant pressure is abnormally high or low.