Heating and Air Conditioning: Description and Operation

1. HEATER BLOWER MOTOR OPERATION
Current is applied at all times through the HTR fuse (40A) to TERMINAL 2 of the Heater Relay.
When the Ignition SW is turned ON, current flows through the HTR fuse (10A) to TERMINAL 3 of the Heater Relay -->the coil side --> TERMINAL 5 --> TERMINAL 8 of the Blower SW.

^ Low Speed Operation
When the Blower SW is moved to Low position, current flows to TERMINAL 8 of the Blower SW --> TERMINAL 1 --> Ground,causing the Heater Relay to Switch ON. This causes the current to flow from the HTR fuse (40A) to TERMINAL 2 of the Heater Relay --> TERMINAL 1 --> TERMINAL 2 of the Blower Motor --> TERMINAL 1 --> TERMINAL 1 of the Blower Resistor --> TERMINAL 4 --> Ground, causing the Blower Motor to rotate at low speed.

^ Medium Speed Operation (Operation At M1, M2)
When the Blower SW is moved to M1 position, current flows to TERMINAL 8 of the Blower SW --> TERMINAL 1 --> Ground,turning the Heater Relay to Switch ON. This causes the current to flow from the HTR fuse (40A) to TERMINAL 2 of the Heater Relay --> TERMINAL 1 --> TERMINAL 2 of the Blower Motor --> TERMINAL 1 --> TERMINAL 1 of the Blower Resistor --> TERMINAL 2 --> TERMINAL 6 of the Blower SW --> TERMINAL 1 --> Ground. At this time, the Blower resistance of the Blower Resistor is less than at Low speed, so the Blower Motor rotates at medium low speed.
When the Blower SW is moved to M2 position, current flows through the Motor flows from TERMINAL 1 of the Blower Resistor to TERMINAL 3 --> TERMINAL 5 of the Blower SW --> TERMINAL 1 --> Ground. At this time, resistance of the Blower Resistor is less than at M1 position, so the Blower Motor rotates at medium high speed.

^ High Speed Operation
when the Blower SW is moved to High position, current flows to TERMINAL 8 of the Blower SW --> TERMINAL 1 --> Ground,turning the Heater Relay to Switch ON.
This causes the current to flow from the HTR fuse (40A) to TERMINAL 2 of the Heater Relay --> TERMINAL 1 --> TERMINAL 2 of the Blower Motor --> TERMINAL 1 --> TERMINAL 4 of the Blower SW --> TERMINAL 1 --> Ground, causing the Blower Motor to rotate at High speed.

2. OPERATION OF AIR INLET CONTROL SERVO MOTOR
^ Switching From Fresh To Recirc
With the Ignition SW turned ON, current flows from the HTR fuse (10A) to TERMINAL 1 of the Air Inlet Control Servo Motor. When the Recirc/Fresh SW is Switched to the Recirc side, current flows from TERMINAL 1 of the Air Inlet Control Servo Motor to TERMINAL 2 --> TERMINAL 17 of the Heater Control SW --> TERMINAL 22 --> Ground. The Motor Rotates and the Damper moves to the Recirc side. When it is in the Recirc position, current is cut inside the Servo Motor and the Damper stops at that position.

^ Switching From Recirc To Fresh
With the Ignition SW turned ON, when the Recirc/Fresh SW is Switched to the fresh side, current flows from TERMINAL 1 of the Air Inlet Control servo Motor to TERMINAL 3 --> TERMINAL 16 of the Heater Control SW --> TERMINAL 22 --> Ground, the Motor rotates and the Damper moves to the fresh side. When it is in the Fresh position, current is cut inside the Servo Motor and the Damper stops at that position.

3. OPERATION OF AIR VENT MODE CONTROL SERVO MOTOR
With the Ignition SW turned ON, current flows from HTR (10A) fuse to TERMINAL 5 of the Air Vent Mode Control Servo Motor --> TERMINAL 6 --> Ground, and the Damper moves to the position of the mode selection SW of the Heater Control Switch ON. When the mode selection SW of the Heater Control SW is moved to DEF position from the Damper in the Face position, current flows from TERMINAL 7 of the Air Vent Mode Control Servo Motor to TERMINAL 3 of the Heater Control SW --> TERMINAL 22 --> Ground. As a result, the Servo Motor operates until the Damper reaches DEF position. When this occurs the current to the Heater Control SW is shut OFF and rotation of the Motor stops. Switching to other modes is controlled by the Servo Motor according the flowing current.
1. Foot/DEF position : Current flows from TERMINAL 4 of the Servo Motor to TERMINAL 4 of the Heater Control SW.
2. Foot position : Current flows from TERMINAL 3 of the Servo Motor to TERMINAL 5 of the Heater Control SW.
3. BI-Level position : Current flows from TERMINAL 2 of the Servo Motor to TERMINAL 6 of the Heater Control SW.
4. Face position : Current flows from TERMINAL 1 of the Servo Motor to TERMINAL 7 of the Heater Control SW