An optical module for an automobile lighting device adapted to selectively emit a principal light beam generated from a principal light source for performing a principal lighting function and a secondary light beam generated from a secondary light source for performing a secondary lighting function. The optical module having a fixed or retractable shield for providing a principal lighting function such as a main beam with or without a cut-off. The optical module further including a retractable reflecting mirror movable from a retracted position, where the mirror does not substantially interfere with the principal light beam, to a working position in which the reflecting mirror is substantially centered on the optical axis of the optical module and oriented so as to give, from light rays issuing from the secondary source, a secondary beam constituting the secondary lighting function.