System Controls

The Manual Temperature Control (MTC):

• Controls blower motor operation, providing four blower speeds (Low, M1, M2, & High).
• Interfaces with the BCM through hardwired circuits.
• Provides temperature setting information to the BCM through a resistor.
• Provides an A/C request, an EBL request, and mode switch setting information to the BCM through a resistive multiplexed circuit.

The Body Control Module (BCM):

• Drives the EBL status indicator in the MTC. Refer to the appropriate article for additional information about rear window defogger operation.
• Drives the electric door actuators (mode, blend, recirc).
• Sends and A/C request, over the PCI Bus, to the PCM when A/C operation is desired.
• Uses Evaporator Temperature Sensor data to prevent evaporator freeze up while maintaining optimum cooling performance.

The MTC HVAC system uses:

• One, five-wire electric blend door actuator.
• One, five-wire electric mode door actuator.
• One, two-wire electric recirculation door actuator.