Blower controls – circuit operation

BLOWER CONTROLS – CIRCUIT OPERATION

CIRCUIT OPERATION

Front Blower

With the Ignition Switch (X134) in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energised, applying battery voltage to the Front Blower Motor Relay (K192). When the Front Fan Speed Switch (X247) is turned to position I, ground is applied to terminal 85 of the Front Blower Motor Relay (K192). The relay is energised, applying battery voltage to terminal 2 of the Front Blower Motor (M101). Ground is applied to the Front Blower Motor (M101) through all three resistors of the Front Blower Resistor Unit (Z214). The Front Blower Motor (M101) then runs at low speed. When the Front Fan Speed Switch (X247) is turned to position II, the Front Blower Motor Relay (K192) remains energised. Battery voltage is still applied to terminal 2 of the Front Blower Motor (M101). Ground is now applied to the Front Blower Motor (M101) through two resistors of the Front Blower Resistor Unit (Z214) and the Front Fan Speed Switch (X247). The motor then runs at the low-medium speed. When the Front Fan Speed Switch (X247) is turned to position III, the Front Blower Motor Relay (K192) remains energised. Ground is now applied to the Front Blower Motor (M101) through one resistor of the Front Blower Resistor Unit (Z214) and the Front Fan Speed Switch (X247). The motor then runs at the medium-high speed. When the Front Fan Speed Switch (X247) is turned to position IV, the Front Blower Motor Relay (K192) remains energised. Ground is now applied directly to the Front Blower Motor (M101) through the Front Fan Speed Switch (X247). The motor then runs at high speed.

Fresh Air Mode

With the Ignition Switch (X134) in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energised, applying battery voltage to the Air Recirculation Solenoid In-Line Fuse (P138) and Air Recirculation Solenoid (K123). When the Air Supply Selector Switch is moved to the Fresh Air position, ground is applied to the Air Recirculation Solenoid (K123). The solenoid now opens the fresh air intake flap allowing fresh air to enter the vehicle cabin. When the fresh air intake flap has been fully opened, the microswitch inside the Air Recirculation Solenoid (K123) moves to the Fresh Air position interrupting the ground supply. The solenoid now stops and remains in the Fresh Air position.

Recirculated Air Mode

With the Ignition Switch (X134) in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energised, applying battery voltage to the Air Recirculation Solenoid In-Line Fuse (P138) and Air Recirculation Solenoid (K123). When the Air Supply Selector Switch is moved to Recirculate Air position, ground is applied to the Air Recirculation Solenoid (K123). The solenoid now closes the fresh air intake flap allowing only the air inside the vehicle cabin to circulate. When the fresh air intake flap has been fully closed, the microswitch inside the Air Recirculation Solenoid (K123) moves to the Recirculate Air position interrupting the ground supply. The solenoid now stops and remains in the Recirculate Air position.