^^^ Normal bulb's in reverse and fog
Now!
It depends how its wired and what type of LEDs you get.More than likely it will be one of two ways. a) Its wired the old fashioned way through a flasher relay. In which case it will flash the lights much quicker and think theres a bulb out. b)Its wired through the canbus system to each bulb and it will show a bulb out fault.