System Controls

The A/C Heater Control:

• is fully addressable with the DRBIII®.
• communicates on the Programmable Communication Interface Multiplex System (PCI) Bus.
• broadcasts an A/C request on the PCI Bus to the Powertrain Control Module (PCM) when compressor operation is desired.
• uses input from the evaporator temperature sensor to prevent evaporator freeze up while maintaining optimum cooling performance.
• has dual-zone temperature control to provide a wide side-to-side variation in temperature to meet the needs of the driver and the front seat passenger.
• broadcasts a blower relay on request on the PCI Bus to the Integrated Power Module (IPM) at power up (power switch on).
• controls EBL operation.
• controls blower operating speed, providing four speed settings (Low, M1, M2 and High).
• controls the electric door actuators' operation.
  • 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 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 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.

The Dual-Zone HVAC system uses:

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

System Relays

• The Integrated Power Module (IPM) houses and provides power to the A/C Clutch Relay, EBL Relay, and the Front Blower Motor Relay.