Heater

Battery voltage is applied through the HTR Fuse to the Blower Speed Selector Switch when the Ignition Switch is in the "ON" position. When the Blower Speed Selector Switch is moved to LOW, system voltage is applied through the closed contacts of the Blower Speed Selector Switch With the Blower Speed Selector Switch in LOW, current must travel all the way through the resistive element in the Blower Motor Resistor before traveling to ground through the Blower Motor. Therefore the reduced voltage potential caused by the Blower Motor Resistor maintains the Blower Motor at LOW speed.

When the Blower Speed Selector Switch is in the M1 position, voltage passes only partially through the Blower Motor Resistor before reaching grimed through the Blower Motor. Since less of the Blower Motor Resistor is part of the circuit, the resistance in the circuit is lower and, in turn, the voltage potential at the Blower Motor is higher. Therefore, the Blower Motor operates at a higher speed than in the LOW position.

M2 operation is identical in M1 operation with the exception that even less of the Blower Motor Resistor is in the circuit. Therefore, Blower Motor operation in M2 is faster than it is in M1.

With the Blower Speed Selector Switch in the HIGH position, voltage bypasses the Blower Motor Resistor entirely and passes directly through the Blower Motor to ground. Therefore, the resistance in the ground path is nearly zero and the Blower Motor operates on full system voltage. Under these conditions, the Blower Motor operates at full speed.