Bill-
The Tridon unit is your heavy duty emergency flasher. On our coach it is mounted loosely on a steel plate, a few inches square, immediately under the access panel on top of the dash in front of the steering wheel. Alongside it are a couple of Deutsche brand connectors and the momentary push button switch in your photo. The switch faces up, and I think it may be for a technician's use when working with some component; I just don't recall offhand what the component is. A call to BCS would reveal the switch's function.
If you have a similar steel mounting plate, your flasher and button likely came loose and fell down, or a tech forgot to replace them following some under-dash service.
Joel