Is the rear fog light and reverse light not working on your Mercedes-Benz GLA250? Learn how to fix the problem by replacing the light bulbs of your vehicle. This guide is a step-by-step procedure for replacing the rear fog light and reverse (backup) light on the Mercedes Benz GLA-Class. This tutorial is based on the 2017 GLA250 X156 chassis.

What you will need

Bestseller No. 1
SYLVANIA - 921 Long Life - High Performance Incandescent Bulb, 35965 (10 Pack)
SYLVANIA – 921 Long Life – High Performance Incandescent Bulb, 35965 (10 Pack)
Stocking #: 921LL. TP; Bulbs per SKU: 10; Bulb Type: Incandescent
  • Prying tool
  • 1235 light bulb
  • 921 light bulb


  1. Remove the trunk door panel. Click on this link to see the step-by-step procedure for removing and installing the trunk panel.Removing the panel on the trunk door.
  2. Locate the rear fog light socket and reverse light socket behind the inner tail light assembly.
  3. Remove the sockets by turning and then pulling them out from the tail light assembly.Removing the brake light socket. Removing the rear fog light socket.
    Removing the reverse light socket.

  4. Remove the rear fog light bulb from the socket by twisting it counterclockwise and pulling it out.The brake light bulb of the Mercedes Benz GLA250.
    Removing the brake light bulb out from the socket.

  5. Line up the new rear fog light bulb to the socket and twist it clockwise to lock it in place.Installing the new brake light bulb.
  6. Remove the reverse light from the socket by pulling it out. Then line up the new reverse light to the socket and push it in to lock it into place.
  7. Reinstall the sockets back to the tail light assembly by pushing them in their original position.
  8. Reinstall the trunk panel. For more help with this step, see this guide. Installing the trunk door panel back to the vehicle.

We hope you find the Replace Back Up Fog Light Bulb Mercedes-Benz 2014–2020 X156 guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

Leave a Reply

Your email address will not be published. Required fields are marked *