The heater and A/C programmer receives the rear defogger request from the heater and A/C control assembly. The HVAC programmer sends a Class 2 message to the body control module (SBM). The SBM controls the following conditions:
| • | The rear defogger on/off status |
| • | The amount of time that the rear defogger is on. |
The SBM communicates the rear defogger status to the HVAC programmer over the Class 2 serial data. The heater and A/C programmer lights the rear defogger indicator accordingly.
The HVAC programmer receives the rear defogger request from the HVAC control assembly. The HVAC programmer then activates the heated mirrors. The HVAC programmer sends a Class 2 serial data message to the driver's door module (DDM). The DDM controls the following conditions:
| • | The driver's heated mirror on/off status. |
| • | The amount of time that the driver's heated mirror is on. |
When the DDM receives the Class 2 request from the HVAC programmer, the DDM communicates to the passenger's door module (PDM) over a simple bus interface (SBI). The PDM controls the following conditions:
| • | The passenger's heated mirror on/off status. |
| • | The amount of time that the passenger's heated mirror is on. |
