Air Conditioning

System Outline

Current is applied at all times through the HTR fuse to TERMINAL 5 of the HTR relay.

When the ignition SW is turned on, the current flows through the GAUGE fuse to TERMINAL 1 of the HTR relay to TERMINAL 2 to TERMINAL 2 of the blower SW.

1. Heater Blower Motor Operation

- Low speed operation
When the blower SW is moved to LO position, the current flows to TERMINAL 2 of the blower SW to TERMINAL 1 to GROUND, causing the HTR relay to turn on. This causes the current flows from the HTR fuse to TERMINAL 5 of the HTR relay to TERMINAL 3 to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 1 of the blower resistor to TERMINAL 4 to GROUND, rotating the blower motor at low speed.

- Medium speed operation (Operation at M1, M2)
When the blower SW is moved to M1 position, the current flows to TERMINAL 2 of the blower SW to TERMINAL 1 to GROUND, causing the HTR relay to turn on. This causes the current flows from the HTR fuse to TERMINAL 5 of the HTR relay to TERMINAL 3 to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 1 of the blower resistor to TERMINAL 2 to TERMINAL 7 of the blower SW to TERMINAL 1 to GROUND. At this time, the blower resistance of the blower resistor is smaller than at low speed, so the blower motor rotates at medium low speed.

When the blower SW is moved to M2 position, the current flows through the HTR relay to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 1 of the blower resistor to TERMINAL 3 to TERMINAL 6 of the blower SW to TERMINAL 1 to GROUND. At this time, resistance of the blower resistor is smaller than at M1 position, so the blower motor rotates at medium high speed.

- High speed operation
When the blower SW is moved to HI position, the current flows to TERMINAL 2 of the blower SW to TERMINAL 1 to GROUND, causing the HTR relay to turn on. This causes the current flows from the HTR fuse to TERMINAL 5 of the HTR relay to TERMINAL 3 to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 10 of the blower SW to TERMINAL 1 to GROUND, rotating the blower motor at high speed.

2. Air Conditioning Operation
When the blower SW is set on, the current flows from the HTR fuse to the HTR relay (Point side) to the A.C fuse to the TERMINAL 3 of the A/C SW. If the A/C SW is turned on, at this time a signal is input into the engine control module. This activates the engine control module. So that current flows from the BA fuse to the A/C magnetic clutch valve to TERMINAL (B) 2 of the engine control module. Causing the compressor to operate.

3. DEF or FOOT & DEF Synchronized Control Function
When the blower SW is on and the heater control lever (Air vent mode control lever) turned to DEF position, it causes A/C to run whether A/C SW is on or not.