System Outline

Current always flows from the HTR fuse (50A) to TERMINAL 1 of the heater relay. When the ignition SW is turned ON, the current from heater (10A) fuse flows to TERMINAL 2 of the air vent mode control servo motor, to the A/C magnetic clutch relay (coil side) TERMINAL 12 of the A/C amplifier, to TERMINAL 1 of the A/C dual pressure SW --> TERMINAL 4 --> TERMINAL 2 of the A/C amplifier and to the heater relay (coil side) --> TERMINAL A-3 of the blower SW (heater control SW)

1. OPERATION OF AIR VENT MODE CONTROL SERVO MOTOR
When the damper is in FACE position and the Bi-level of the mode dial SW (heater control SW) is then turned ON, current flows from TERMINAL B-7 of the mode dial SW (heater control SW) --> TERMINAL 5 of the air vent mode control servo 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 (10A) fuse to the servo motor, causing the servo motor to operate and the damper to move to Bi-level position. When the damper reaches Bi-level 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 Bi-level.
When another mode position is switched to, input of signals into TERMINAL 'A' and TERMINAL 'B' of the control circuit that ground is not made (as explained above) activates the control circuit and moves the servo motor to the desired position.

2. AIR CONDITIONING OPERATION
When the blower SW (heater control SW) is ON, current flows the HEATER (10A) fuse to the heater relay (coil side) --> TERMINAL A-3 of the Blower SW (heater control SW) --> TERMINAL A-1 --> GROUND, activating the heater relay. This causes current to flow from the HTR (50A) fuse to the heater relay (point side) --> A/C fuse --> TERMINAL 4 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. This activates the A/C amplifier and A/C magnetic clutch relay so that current flows from the HEATER (10A) fuse to the A/C magnetic clutch relay (point side) --> A/C magnetic clutch causing the compressor to operate. The VSV (for A/C idle-up) is turned ON simultaneously to prevent a decrease in engine speed due to A/C operation.