Heated Outside Rearview Mirror
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The DDS and PDS control the activation of the mirror heaters. Upon receiving a serial data message indicating a request for heated mirrors, the DDS and PDS, will apply voltage to the mirror heater element supply voltage circuit. The mirror heaters will remain active until a new message is received indicating rear defogger is to be deactivated.