Abstract: A multifunction signal switch assembly suited for use in heavy duty trucks or the like requiring a rugged installation which can be readily dismantled and reassembled for convenient maintenance. The switch mechanism includes easily replaceable plug-in contact modules and a simple pilot light arrangement which renders the apparatus compatible with most standard two or three terminal flasher systems typicall used in the industry. The apparatus, in addition to the conventional turn signal and hazard warning functions, also supplies an additional function that can be wired, atthe user's option, into any number of automotive related circuits such as a headlight dimming circuit or the like.