Control Module HVAC: Description and Operation

The blower motor controller module contains solid state circuitry which utilizes a pulse width voltage signal (at a given duty cycle), from the control head and returns an inverse pulse width signal to the blower motor see illustration. The control head pulse width signal is based on the user set temperature, outside air temperature, in vehicle temperature and solar sensor. For example, if the in vehicle temperature is much colder or hotter than the user set temperature, and the AUTO button has been selected, the blower motor controller module will control the blower from a high speed to a low speed as the difference in set temperature and in vehicle temperature decreases.