Hi
This is a Dodgy dealer trick, pop the bulb and hey presto no faults
But on the s-types its a led, not sure about the x-type, but its most probably the same
the led is easily removed also, the light should light up and then go out, same as with the others, like airbags, abs, these are also usually checked on a mot
you might have to remove the clock/dash to be sure
looking at dashes on ebay, there no bulbs at rear, so there led's and its just a few clips to them apart, so at a guess, they have popped the led off the board
cheers
Joe