System Controls

The A/C-Heater Control Module:

• is fully addressable with the DRBIII®.
• communicates over the Programmable Communication Interface Multiplex System (PCI) Bus.
• provides an A/C request to the Powertrain Control Module (PCM) over the PCI Bus when compressor operation is desired.
• controls EBL operation.
• controls blower motor operation, providing four blower speeds (Low, M1, M2, & High).
• controls electric door actuator operation.

The Single-Zone HVAC system uses:

• one, two-wire electric blend door actuator.
• two, two-wire electric mode door actuators.
• one, two-wire electric recirculation door actuator.

A simplified control system for operation of the mode, recirculation, and temperature control actuators provides positive positioning without the complexity of feedback from position sensors. The A/C Heater Control Module knows the number of operating actuator revolutions required for full door travel as well as the number of actuator commutator pulses per revolution. Using these parameters, the A/C Heater Control Module runs the actuator for the number of commutator pulses that correspond to the desired door position. To maintain accuracy, the system recalibrates itself periodically at known zero and full travel conditions.