A vehicular exterior rearview mirror assembly includes a mounting structure, a mirror reflective element, a mirror back plate, a heater element, and a blind zone indication module. The heater element is disposed between the mirror back plate and the mirror reflective element. The blind zone indication module includes a diffuser and a housing that houses a circuit element and a light source. The circuit element includes electrically conductive terminals that are in electrical connection with circuitry of the circuit element and that are disposed at a connector portion of the housing that is configured to connect to a wire harness to electrically power circuitry of the circuit element when the vehicular exterior rearview mirror assembly is mounted at a vehicle and used. The blind zone indication module is associated with a blind spot detection system of the vehicle at which the vehicular exterior rearview mirror assembly is mounted.