Metro L3-061 1.0L VIN 6 TBI (1998)
Blower Motor: Description and Operation
HVAC Blower Controls Circuit Description
Battery voltage is applied through the HEATER 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 the LOW position, system voltage is applied through the closed contacts of the blower speed selector switch.
With the blower speed selector switch in the LOW position, current must travel all the way through the resistive element in the blower motor resistor
before traveling to ground through the blower motor. 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 ground
through the blower motor. Circuit resistance is lower because less of the blower motor resistor is part of the circuit. Therefore, the voltage potential at the
blower motor is higher and the blower motor operates at a higher speed than in the LOW position.
The M2 operation is identical to the M1 operation with the exception that even less of the blower motor resistor is in the circuit. The blower motor
operation in M2 is faster than the operation is in M1.
With the blower speed selector switch in the HIGH position voltage bypasses the blower motor resistor entirely. The voltage passes directly through the
blower motor to ground. The resistance in the ground path is nearly 0 and the blower motor operates on full system voltage at full speed.
