Do not touch light bulbs with bare hands as that can shorten the life of the light bulb.
Installing LED bulbs:
If you are upgrading to LED light bulbs, and the bulb doesn't turn on when you install it simply remove the LED bulb and rotate it 180 degrees and reinstall it.
Certain vehicles may trigger a fault message stating faulty or burned light bulb when the original bulb has been upgraded to LED. If that is the case, use halogen bulb or get an Error Free LED bulb.
Replace Back Up Fog Light Bulb Mercedes-Benz 2014–2020 X156 Step-by-step procedure on how to replace the rear fog light and reverse (back-up) light on Mercedes Benz GLA-Class. This tutorial is based on a 2017 GLA250 X156 chassis.