A modular rearview mirror assembly for vehicles incorporates a housing into the mirror assembly case for supporting an electronic control module to reduce the vibration, to ease the installation of the components in the mirror assembly, and to improve access to the various components in the mirror assembly for maintenance or repair. The rearview mirror assembly includes a reflective element, at least one electrical component mounted to the reflective element, and a case housing the reflective element and the electrical component. An electronic control module is supported by the case which communicates with the electrical component. Preferably, the electronic control module is supported by a housing that is either molded with the case or welded to the inner surface of the case to support the electronic control module independently from the electrical component.