System Outline

Current always flows from the HTR fuse to TERMINAL 1 of the HTR relay. When the ignition SW is turned ON, the current from HEATER fuse flows to TERMINAL 6 of the air vent mode control servo motor, to the MG CLT relay (Coil side) to TERMINAL MGC of the A/C amplifier or TERMINAL MGC of the engine control module, to TERMINAL 1 of the A/C dual pressure SW to TERMINAL 4 to TERMINAL +B of the A/C amplifier or TERMINAL PRS of the engine control module, current also and to the HTR relay (Coil side) to TERMINAL 3 of the blower SW.

1. AIR VENT MODE CONTROL SERVO MOTOR OPERATION
When the damper is in FACE position and B/L mode on the heater control SW is selected, current flows from TERMINAL 7 of the heater control SW to TERMINAL 2 of the air vent mode control serve motor so that a signal that the ground circuit is activated is input into TERMINAL B of the control circuit inside the air vent mode control servo motor. Simultaneously, a signal that the ground circuit is not activated is input into TERMINAL A of the control circuit inside the servo motor. These two signals activate the control circuit so that current flows from the HEATER fuse to the servo motor, causing the servo motor to operate and the damper to move to B/L position. When the damper reaches B/L position. A ground cut signal is input into TERMINAL B of the control circuit, the control circuit operates, the servo motor stops rotating and the damper stops at B/L. When another mode position is selected, input of signals into TERMINAL A and TERMINAL B of the control circuit that ground is made or not (as explained above) activates the control circuit and moves the serve motor to the desired position.

2. AIR CONDITIONING OPERATION
When the blower SW is ON, current flows from the HEATER fuse to the HTR relay (Coil side) to TERMINAL 3 of the blower SW to TERMINAL 1 to GROUND, activating the HTR relay. This causes current to flow from the HTR fuse to the HTR relay (Point side) to A/C fuse to TERMINAL 2 of the A/C SW. If the A/C SW is turned ON at this time, a signal is input into the A/C amplifier or engine control module. This activates the A/C amplifier or engine control module and MG CLT relay so that current flows from the HEATER fuse to the MG CLT relay (Point side) to A/C magnetic clutch. Causing The compressor to operate.

When blower SW is ON and heater control SW is at DEF position, it causes A/C to run whether A/C SW is ON or not.