Heater Blower

HEATER BLOWER

DESCRIPTION

General
The heater is operated from three rotary controls located in the centre console. Two of the controls operate the temperature and air flow distribution. The third control operates the four speed blower motor.

A resistor pack is mounted on the RH side of the heater unit. The resistor pack supplies reduced voltages to the blower motor for fan speed one, two, and three. Fan speed drives the blower motor at full speed with a direct 12V supply.

The blower motor will only operate when the ignition switch is in the 'ignition' position.

OPERATION

General
Feed from the positive battery terminal (C0192) is supplied to fusible link 1 of the engine compartment fuse box (C0632) on an R wire. Fusible link 1 is connected in series with fuse 8 and fusible link 2, which are also located in the engine compartment fuse box.

Fusible link 2 (C0571) is connected to the ignition switch (C0028) by an NR wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 4 of the passenger compartment fuse box (C0588) on an SU wire. Fuse 4 (C0586) provides an ignition feed to the following on G then LGS wires:
- The fresh/recirculated air motor (C0006).
- The fresh/recirculated air switch (C0750).
- The blower motor switch (C0058).

Blower Speed 1
If blower speed 1 is selected, current flows across the blower motor switch (C0058) to the resistor pack (C0425) on an RK wire. The resistor pack (C0425) is connected to the blower motor (C0056) by a GK then G wire. As current has to flow through the greatest value resistor, the blower motor operates at slow speed.

The blower motor (C0056) is earthed on a B wire.

Blower Speed 2
If blower speed 2 is selected, current flows across the blower motor switch (C0058) to the resistor pack (C0425) on an RY wire. The resistor pack (C0425) is connected to the blower motor (C0056) by a GK then G wire. As current has to flow through the medium value resistor, the blower motor operates at a slightly increased speed.