LOW-M2 Positions

When the ignition switch is in the RUN position, voltage is applied through the HVAC Fuse 6 (20A), the ignition 3 voltage circuit of the HVAC control, to the HVAC control (selector switch). When the selector switch is switched to any position, except OFF, voltage is supplied to the blower switch through the A/C request signal circuit.

When the blower switch is in position 1 (low), voltage is applied to the blower switch, the blower resistor, the blower motor relay and the blower motor. When voltage is applied to the blower motor, the motor runs at low speed.

When the blower switch is switched to position 2 (M1) or 3 (M2), the blower control system works as described above except for the speed of the blower motor. The blower motor has several resistors that voltage flows through depending which position the blower switch is in. In position 1 (low), voltage passes through 4 resistors. In position 2 (M1), voltage passes 3 resistors and in position 3 (M2) voltage passes through 2 resistors. As the resistance is decreased the blower runs at a faster speed.

HIGH Position

When the blower switch is moved to position 4 (high), voltage is applied through the HVAC control (selector switch) to the blower motor relay. The relay energizes, turning on the blower motor. This causes the motor to run at its fastest speed due to the fact that there is no resistor in the voltage path to the blower motor.