Hombre XS Space Cab 2WD V6-4.3L (1998)
Blower Motor: Description and Operation
CIRCUIT OPERATION
Voltage is supplied to the Heater and A/C Controller by fuse 9 Power to the Blower Motor is supplied through the Mode Selector Switch in the DEF,
BLEND, HEAT, VENT, BI-LEVEL, NORM, and MAX A/C positions. Splice S215 splits the power source between the Blower Motor Resistor and the
Blower Switch. As long as the Mode Selector Switch is in one of the powered positions, power will always be present at cavity B of the Blower Motor
Resistor. In the low position, voltage passes through all three resistors in the Blower Motor Resistor, through the Blower Motor relay and to the blower
motor. In medium 1, voltage passes through two resistors, and in medium 2, voltage goes through one resistor. The high position supplies trigger voltage
to the Blower Motor Relay. This energizes the Blower Motor Relay arid supplies full battery voltage to the Blower Motor through the HVAC fuse in the
Underhood Bussed Electrical Center (UBEC) and ground is provided at G117.
Heater Blower Controls
Voltage is supplied to the HVAC control by the HVAC fuse 9. Power to the Blower Motor is supplied through the Mode selector switch in the DEF,
BLEND, HEAT, VENT, and BI-LEVEL positions. Splice S215 splits the power source between the Blower Motor Resistor and the blower switch. As
long as the Mode selector switch is in one of the mode positions, voltage will always be present at cavity B of the Blower Motor Resistor. In the low
position, voltage passes through all three resistors, through the Blower Motor Relay and though the Blower Motor. In medium 1, current is reduced
through the two resistors of the Blower Motor Resistor and decreases the fan speed. In Medium 2, current is increased going through only one resistor
and increases the fan speed. In High, the current bypasses the Blower Motor Resistor and energizes the Blower Motor Relay. The relay supplies full
battery voltage to the Blower Motor through the HVAC fuse in the Underhood Bussed Electrical Center (UBEC).
