I am not familiar with your coach at all but usually fog lights are operated via a relay which in turn is probably operated by the dash switch. So it is possible that the fog light relay has failed closed.....or the switch has shorted to operate the fod light relay. Find the relay and pull it to see if your lights turn off and then use a multimeter to test the relay and switch +12V at the relay coil socket terminals. Of course I am assuming your coach uses a relay......hope that helps.
__________________
|