The blower motor pulse width module (PWM) contains solid-state
circuitry which uses a pulse width voltage signal (at a given duty cycle),
from the control head. The PWM then returns and inverse pulse width signal
to the blower motor.
The control head pulse width signals are based on the following conditions:
| • | The blower and mode selections |
| • | The user-set temperature |
| • | The in-vehicle temperature |
| • | The outside air temperature |
| • | The solar (sun load) sensor |
If the in-vehicle temperature is much hotter or colder than the user-set
temperature, and AUTO mode has been selected, the control module enables the
blower motor to run at high speed. As the set temperature approaches, the
control module cuts the voltage to the motor and the speed decreases.
Fan speed
Pressing the fan speed button will manually lock in the current fan
speed and stop the automatic fan speed control. Pressing the arrows will delete
AUTO from the digital display. The fan graphics with the fan speed will be
shown. To increase the fan speed so that more air flows into the vehicle,
press the UP arrow on the fan switch. To decrease the fan speed so that less
air flows into the vehicle, press the DOWN arrow on the fan switch. The AUTO
button must be pressed to return to the automatic fan control.
