Blower Motor Speed Control

^ The blower motor runs in all mode positions except the OFF position when the ignition switch is in the RUN position.
^ The blower motor speed is controlled by a four-position electrical blower motor speed control switch. The switch is located at the left side of the control.
^ The blower motor speed control switch provides a choice of the following speeds:
^ Low
^ Medium (two settings)
^ High
^ Power is routed from the HVAC fuse in the fuse block to the mode control switch.
^ The mode control switch breaks the circuit when the switch is in the OFF position. The switch closes the circuit in all other positions.
^ From the mode control switch the circuit goes to the blower motor speed control switch.
^ When the blower motor speed control switch is turned to the LOW setting, voltage is conducted to the resistor. At the resistor, the voltage passes through all three resistors and is reduced to provide the low blower motor speed.
^ When the blower switch is in either of the two medium speed positions, the switch closes. This action sends voltage through one or two of the resistors. Because the current follows the path of least resistance, the circuit branch that leads directly to all three resistors becomes ineffective. At this point the current bypasses either one or two resistors, depending upon which medium speed position is selected. The reduced resistance increases the current flow and blower motor speed.
^ When the blower motor switch is turned to the HIGH setting, the action energizes the high blower relay. Power is taken from a separate circuit that is protected by a fusible link. The separate power circuit is hot at all times. The circuit has the capacity to handle the current demands of the blower motor at high speed.
^ The circuit to the blower motor is completed to ground at the instrument panel through the instrument panel wiring harness.