Heating and Air Conditioning: Description and Operation
SYSTEM OUTLINE1. HEATER BLOWER MOTOR OPERATION
Current is applied at all times through the HEATER fuse to TERMINAL 1 of the HEATER relay.
When the ignition SW is turned on, current flows through the HEATER fuse to TERMINAL 3 of the HEATER relay to TERMINAL 5 to TERMINAL 8 of the blower SW.
- Low speed operation
When the blower SW is moved to LO position, the current to TERMINAL 8 of the blower SW flows to TERMINAL 1 to GROUND, causing the HEATER relay is turned on. This causes the current to flow from the HEATER fuse to TERMINAL (B) 1 of the HEATER relay to TERMINAL 2 to TERMINAL 2 of the blower motor to TERMINAL 1 to TERMINAL 1 of the blower resistor to TERMINAL 4 to 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, the current to TERMINAL 8 of the blower SW flows to TERMINAL 1 to GROUND, turns the HEATER relay on. This causes the current to flow from the HEATER fuse to TERMINAL 1 of the HEATER relay to TERMINAL 2 to TERMINAL 2 of the blower motor to TERMINAL 1 to TERMINAL 1 of the blower resistor to TERMINAL 2 to TERMINAL 6 of the blower SW to TERMINAL 1 to 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 flowing through the motor flows from TERMINAL 1 of the blower resistor to TERMINAL 3 to TERMINAL 5 of the blower SW to TERMINAL 1 to 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 HI position, the current flows to TERMINAL 8 of the blower SW to TERMINAL 1 to GROUND and turns the HEATER relay on.
This causes the current to flow from the HEATER fuse to TERMINAL 1 of the HEATER relay to TERMINAL 2 to TERMINAL 2 of the blower motor to TERMINAL 1 to TERMINAL 4 of the blower SW to TERMINAL 1 to GROUND, causing the blower motor to rotate at high speed.
2. AIR CONDITIONING OPERATION
If the A/C control SW is turned on when the blower SW is set to on, A/C operation starts. However, when the mode SW is at DEF or FOOT/DEF position, forcibly the air intake is set to FRESH mode and the A/C operates.