Air Conditioning (Automatic A/C)
SYSTEM OUTLINE1. HEATER BLOWER MOTOR OPERATION
Current is applied at all times through HEATER fuse to TERMINAL 1 of the HEATER relay. When the ignition SW is turned on, current flows through the GAUGE fuse to TERMINAL 5 of the HEATER relay to TERMINAL 3 to TERMINAL HR of the A/C amplifier. At the same time, current also flows from GAUGE fuse to TERMINAL IG+ of the A/C amplifier.
- Low speed operation
When the blower SW (Heater control panel SW) is pushed to LOW SPEED position, the current to TERMINAL HR of the A/C amplifier flows to TERMINAL GND of the A/C amplifier to GROUND and turns the HEATER relay on. As a result, the current to TERMINAL 1 of the HEATER relay flows to TERMINAL 2 of the relay to TERMINAL 2 of the blower motor to TERMINAL 1 to TERMINAL 2 of the blower resistor (Low) to TERMINAL 1 to GROUND and causes the blower motor to rotate at low speed.
- High speed operation
When the blower SW (Heater control panel SW) is pushed to HIGH SPEED position, the current to TERMINAL HR of the A/C amplifier flows to TERMINAL GND of the A/C amplifier to GROUND and turns the HEATER relay on. As a result, the current to TERMINAL 1 of the HEATER relay flows to TERMINAL 2 to TERMINAL 2 of the blower motor to TERMINAL 1 to TERMINAL 4 of the blower motor linear controller to TERMINAL 2 to TERMINAL BLW of the A/C amplifier (Which is activated when the blower SW is pushed to high speed position) to TERMINAL GND to GROUND without passing through the blower resistor (Low), causing the blower motor to rotate at high speed.
2. AIR INLET CONTROL SERVO MOTOR OPERATION
(Switching from FRESH to RECIRC)
With the ignition SW turned on, the current flows from GAUGE fuse to TERMINAL IG+ of the A/C amplifier to TERMINAL AIR to TERMINAL 1 of the air inlet control servo motor to TERMINAL 2 to TERMINAL A/F of the A/C amplifier to TERMINAL GND to GROUND, the motor rotates and the damper moves to the RECIRC side. when the damper operates with the heater control panel SW at RECIRC position, the damper position signal is input from TERMINAL 3 of the servo motor to TERMINAL TPI of the A/C amplifier. As a result, current to the servo motor circuit is cut off by the A/C amplifier, so the damper stops at that position.
(Switching from RECIRC to FRESH)
With the ignition SW turned on, when the heater control panel SW is switched to the FRESH side, the current flows from TERMINAL IG+ of the A/C amplifier to TERMINAL A/F to TERMINAL 2 of the air inlet control servo motor to TERMINAL 1 to TERMINAL AIR of the A/C amplifier to TERMINAL GND to GROUND, The motor rotates and the damper stops at that position.
3. AIR VENT MODE CONTROL SERVO MOTOR OPERATION
When the ignition SW turned on, the current flows from GAUGE fuse to TERMINAL IG+ of the A/C amplifier.
(Switching from DEF to FACE)
The current flows from TERMINAL FACE of the A/C amplifier to TERMINAL 4 of the air vent mode control servo motor to TERMINAL 8 to TERMINAL DEF of the A/C amplifier to TERMINAL GND to GROUND. The motor rotates and the damper moves to the FACE side. When the damper operates with the heater control panel SW at FACE position, the damper position signal is input from TERMINAL 8 of the servo motor to the TERMINAL DEF of the A/C amplifier. As a result, current to the servo motor circuit is cut off by the A/C amplifier, so the damper stops at that position.
(Switching from FACE to DEF)
The current flows from TERMINAL DEF of the A/C amplifier to TERMINAL B of the air vent control servo motor to TERMINAL 4 to TERMINAL FACE of the A/C amplifier to TERMINAL GND to GROUND, the motor rotates and the damper stops at that position.
4. AIR MIX CONTROL SERVO MOTOR OPERATION
When the temperature control SW (Heater control panel SW) is turned to the "COOL" side the current flows from TERMINAL AMC of the A/C amplifier to TERMINAL 2 of the air mix control servo motor to motor to TERMINAL 4 to TERMINAL AMH of the A/C amplifier to GROUND and the motor rotates. The damper opening angle at this time is input from TERMINAL 7 of the servo motor to TERMINAL TP of the A/C amplifier, this is used to determine the DAMPER STOP position and maintain the set temperature.
When the temperature control SW (Heater control panel SW) is turned to the "HOT" side, the current flows from servo motor to TERMINAL AMH of the A/C amplifier to TERMINAL 4 of the air mix control servo motor to motor to TERMINAL 2 to TERMINAL AMC of the A/C amplifier, rotating the motor in reverse and switching the damper from "COOL" to "HOT" side.
5. AIR CONDITIONING OPERATION
The A/C amplifier receives various signals, I.E., out side air temperature signal from the A/C ambient temperature sensor, coolant temperature from water temperature sensor, etc.
When the engine is started and the A/C SW (Heater control panel SW) is on, a signal is input to the A/C amplifier.
As a result, the ground circuit in A/C amplifier is closed and current flows from GAUGE fuse to TERMINAL 1 of the A/C magnetic clutch relay to TERMINAL 4 to TERMINAL MGC of the A/C amplifier to TERMINAL GND to GROUND, turning the A/C 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 detects the magnetic clutch is on and the A/C compressor operates. If the A/C amplifier detects the following conditions, it stops the air conditioning:
- Evaporator outlet air is too low.
- The refrigerant pressure is abnormally high or abnormally low.
- The engine speed is too low.
- Rapid acceleration occurs.