check both bulbs.
check fuse.
put into reverse, with ignition on, then wiggle the gearstick. if they flash, its switch adjustment, if they dont, more than likely the switch has packed up.
its screwed to the side of the gearlever, bit fiddly.
tony
March 2011
I can answer this question...
Mercedes Vito Van 2006 my reversing lights have failed how can I fix them?