Automatic Climate Controls
DESCRIPTIONBlower motor speed is controlled by the solid state blower control module, which follows commands from the Heating Ventilation and Air Conditioning (HVAC) programmer. The HVAC programmer, in turn, determines the proper blower speed using information from the heater and A/C control assembly and its network of sensors.
OPERATION
The HVAC programmer's blower speed command to the blower control module is a continuously varying voltage (between about 2 and 8 volts). With a voltage signal of about 2 volts from the HVAC programmer, the blower control module outputs about 4 volts to run the blower motor at its slowest speed. With a voltage signal of -about 8 volts from the programmer, the blower control module outputs battery voltage to run the blower motor at maximum speed.
The blower can be operated in either manual fan mode or AUTO fan mode. In manual fan mode, five different fan speeds are available and, once selected, fan speed remains constant until a new speed is selected from the heater and A/C control assembly.
In AUTO fan mode, blower speed is infinitely variable (between the minimum and maximum speeds and varies automatically according to conditions monitored by the HVAC programmer's network of sensors. Sensors that provide information that may affect blower speed in AUTO mode include: the in-vehicle temperature sensor, ambient temperature sensor, solar sensor and vehicle speed sensor