An accessory mounting system for mounting an accessory at a windshield of a vehicle includes an accessory adapted for mounting at and demounting from a receiving structure adhesively attached by an adhesive to an interior surface of a vehicle windshield. The accessory includes a camera and circuitry. With the accessory received and supported by the receiving structure and with the receiving structure adhesively attached by an adhesive to an interior surface of a vehicle windshield, (i) the accessory receives an input from the equipped vehicle via a CAN bus communication and delivers an output to the equipped vehicle via a CAN bus communication, and (ii) the camera views forwardly through the windshield via a light transmitting portion of a light absorbing layer of the windshield of the equipped vehicle, with the light absorbing layer otherwise hiding the accessory from view through the windshield from external the equipped vehicle.