On vehicles equipped with heated outside rearview mirrors (OSRV), the driver door module (DDM) and passenger door module (PDM) controls the activation of the mirror heaters. Upon receiving a Class 2 message indicating a request for heated mirrors, the DDM (and PDM for the passenger side) will activate the mirror heater output. The mirror heaters will remain active until a new message is received indicating rear defogger is to be deactivated (either by driver input or by expiration of a calibrated timer).