1992 Toyota Previa Electrical Supplement

(Tam Dominh) #1

~ AIR CONDITIONER


SYSTEM OUTLINE



  1. FRONT HEATER BLOWER MOTOR OPERATION
    WITH THE IGNITION SW ON. CURRENT FLOWING THROUGH THE AIC FUSE FLOWS TO TERMINAL 3 OF THE HEATER RELAY ~ TERMINAL 5
    ~ TERMINAL 5 OF THE HEATER BLOWER SW.
    (LOW SPEED OPERATION)
    WHEN THE HEATER BLOWER SW IS MOVED TO LOW SPEED POSITION. THE CURRENT FLOWING TO TERMINAL 5 OF THE BLOWER SW FLOWS TO
    TERMINAL 6 ~ GROUND. TURNING THE HEATER RELAY ON. THEN CURRENT FLOWS FROM 40A HEATER CB TO TERMINAL 1 OF THE HEATER
    RELAY ~ TERMINAL 2 ~ TERMINAL 2 OF THE BLOWER MOTOR ~ TERMINAL 1 ~ TERMINAL 1 OF THE BLOWER RESISTOR ~
    TERMINAL 4 ~ GROUND. CAUSI NG THE BLOWER MOTOR TO ROT A TE. AT TH IS TI ME. THE CURRENT FLOWS AGA I NST THE FULL
    RESISTANCE OF THE BLOWER RESISTOR. SO THE MOTOR TURNS SLOWLY AT LOW SPEED.
    (OPERATION AT SPEED Ml (I) M2 (II))
    WHEN THE BLOWER SW I S MOVED TO M 1 SPEED POS IT ION. THE CURRENT FLOW I NG TO TERMINAL 5 OF THE BLOWER SW FLOWS TO
    TERMINAL 6 ~ GROUND. TURNING THE HEATER RELAY TO ON. THEN THE SAME AS FOR LOW SPEED. CURRENT FLOWING THROUGH HEATER
    CB FLOWS FROM HEATER RELAY ~ BLOWER MOTOR ~ TERMINAL 1 OF THE BLOWER RESISTOR ~ TERMINAL 2 ~ TERMINAL 1 OF
    THE BLOWER SW ~ TERMINAL 6 ~ GROUND. THIS TIME THE RESISTANCE OF THE BLOWER RESISTOR IS LESS THAN AT LOW SPEED
    SO THE BLOWER MOTOR TURNS FASTER THAN AT LOW SPEED. WHEN THE SW IS MOVED TO M2 SPEED POSITION. CURRENT FLOWING THROUGH
    THE MOTOR FLOWS FROM TERMINAL 1 OF THE BLOWER RESISTOR ~ TERMINAL 3 ~ TERMINAL 2 OF THE BLOWER SW ~
    TERMINAL 6 ~ GROUND. THIS TIME. RESISTANCE OF THE BLOWER RESISTOR IS LESS THAN AT Ml SPEED. SO THE BLOWER MOTOR
    TURNS EVEN FASTER THAN AT Ml SPEED.
    (HIGH SPEED OPERATION)
    WHEN THE BLOWER SW IS MOVED TO HIGH SPEED POSITION. THE HEATER RELAY AND FRONT HEATER (HI) RELAY TURNS ON THE CURRENT
    FLOWING THROUGH THE BLOWER MOTOR FLOWS TO TERMINAL 2 OF THE FRONT HEATER RELAY ~ TERMINAL 1 ~ GROUND. AND BY NOT
    FLOWING THE THROUGH BLOWER RESISTOR. THE BLOWER MOTOR TURNS AT THE HIGHEST SPEED. HIGH SPEED.

  2. REAR BLOWER MOTOR OPERATION
    (DENSO TYPE)
    WHEN THE IGNITION SW IS TURNED ON. THE CURRENT FLOWING THROUGH THE AIC FUSE FLOWS FROM TERMINAL 5 OF THE REAR AIC
    RELAY ~ TERMINAL 2 ~ TERMINAL 4 OF THE REAR AIC SW.
    (LOW SPEED OPERATION)
    WHEN THE REAR AlC SW IS MOVED TO LOW SPEED POSITION. CURRENT FLOWING TO TERMINAL 5 OF THE REAR AIC RELAY FLOWS TO
    TERMINAL 2 ~ TERMINAL 4 OF THE REAR AIC SW ~ TERMINAL 2 ~ GROUND. TURNING THE REAR AlC RELAY ON. THEN CURRENT
    FLOWS FROM THE AIC FUSE (FOR REAR) TO TERMINAL 1 OF THE REAR AIC RELAY ~ TERMINAL 3 ~ TERMINAL 2 OF THE BLOWER
    MOTORS ~ TERMINAL 1 ~ TERMINAL 1 OF THE BLOWER RESISTOR ~ TERMINAL 3 ~ GROUND. CAUSING THE BLOWER MOTOR TO
    TURN. THIS TIME. CURRENT FLOWS AGAINST THE FULL RESISTANCE OF THE BLOWER RESISTOR SO THE MOTOR TURNS SLOWLY AT LOW
    SPEED.
    (MIDDLE SPEED OPERATION)
    WITH THE REAR AIC SW IS MOVED TO MIDDLE!I) POSITION. CURRiNT FLOWING THROUGH THE BLOWER MOTOR FLOWS TO TERMINAL 1 OF
    THE BLOWER RESISTOR ~ TERMINAL 2 ~ TERMINAL 1 OF THE REAR AIC SW ~ TERMINAL 3 ~ GROUND. THIS TIME. THE
    RESISTANCE OF THE BLOWER RESISTOR IS LESS THAN THAT AT LOW SPEED AND THE BLOWER MOTOR TURNS FASTER THAN WHEN AT LOW
    SPEED.
    (HIGH SPEED OPERATION)
    WITH THE REAR AIC SW IS MOVED TO HIGH POSITION. CURRENT FLOWING THROUGH THE BLOWER MOTOR FLOWS. WITHOUT PASSING
    THROUGH THE BLOWER RESISTOR. TO TERMINAL 2 OF THE REAR AIC SW ~ TERMINAL 3 ~ GROUND. SO THAT THE BLOWER MOTOR
    TURNS AT THE HIGHEST SPEED.
    (PANASONIC TYPE)
    WHEN THE IGNITION SW IS TURNED ON. THE CURRENT FLOWING THROUGH THE AIC FUSE FLOWS FROM TERMINAL 5 OF THE REAR AIC
    RELAY ~ TERMINAL 2 ~ TERMINAL 4 OF THE REAR AlC SW.
    (LOW SPEED OPERATION)
    WHEN THE REAR AIC SW IS MOVED TO LOW SPEED POSITION. CURRENT FLOWING TO TERMINAL 5 OF THE REAR AIC RELAY FLOWS TO
    TERMINAL 2 ~ TERMINAL 4 OF THE REAR AIC SW ~ TERMINAL 3 ~ GROUND. TURNING THE REAR AIC RELAY ON. THEN CURRENT
    FLOWS FROM THE AIC FUSE (FOR REAR) TO TERMINAL 1 OF THE REAR AIC Rf'LAY ~ TERMINAL 3 ~ TERMINAL 1 OF THE BLOWER
    MOTORS'~ TERMINAL 2 ~ TERMINAL 3 OF THE BLOWER RESISTOR ~ TERMINAL 2 ~ GROUND. CAUSING THE BLOWER MOTOR TO
    TURN. TH I S TI ME. CURRENT FLOWS AGA I NST THE FULL RES I STANCE OF THE BLOWER RES I STOR SO THE MOTOR TURNS SLOWLY AT LOW
    SPEED.
    (MIDDLE SPEED OPERATION)
    WITH THE REAR AIC SW IS MOVED TO MIDDLE!I) POSITION. CURRENT FLOWING THROUGH THE BLOWER MOTOR FLOWS TO TERMINAL 3 OF
    THE BLOWER RESISTOR ~ TERMINAL 1 ~ TERMINAL 1 OF THE REAR AlC SW ~ TERMINAL 3 ~ GROUND. THIS TIME.
    THE RESISTANCE OF THE BLOWER RESISTOR IS LESS THAN THAT AT LOW SPEED AND THE BLOWER MOTOR TURNS FASTER THAN WHEN AT
    LOW SPEED.

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