Heating and Air Conditioning: Description and Operation
SYSTEM OUTLINE1. HEATER BLOWER MOTOR OPERATION
Current is applied at all times through the HTR fuse (50 A) to TERMINAL 5 of the heater relay.
When the ignition SW is turned on, current flows through the HTR fuse (10 A) to TERMINAL 2 of the heater relay to the coil side to TERMINAL 1 to TERMINAL 8 of the blower SW.
- Low speed operation
When the blower SW is moved to LO position, current flows to TERMINAL 8 of the blower SW to TERMINAL 1 to GROUND, causing the heater relay to switch on. This causes the current to flow from the HTR fuse (50 A) to TERMINAL 5 of the heater 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, 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 to TERMINAL 1 to GROUND, turning the heater relay to switch on. This causes the current to flow from the HTR fuse (50 A) to TERMINAL 5 of the heater 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 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 flows 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 HIGH position, current flows to TERMINAL 8 of the blower SW to TERMINAL 1 to GROUND, turning the heater relay to switch on.
This causes the current to flow from the HTR fuse (50 A) to TERMINAL 5 of the heater relay to TERMINAL 3 to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 4 of the blower SW to TERMINAL 1 to GROUND, causing the blower motor to rotate at high speed.