Fix Fading or Broken DRLs on Your Mercedes-Benz W213 (2016-2023): Complete Replacement Guide

TL;DR

If your 2016-2023 Mercedes-Benz W213 E-Class has dim, yellowed, or completely dead daytime running lights (DRLs), the culprit is often the light guide strip or its LED board, not the headlight assembly. Replacing these components with a new Mercedes-Benz E-Class W213 DRL Light Guide Strip & LED Board (2016-2019) restores crisp, bright DRLs without replacing the entire headlight.

What Goes Wrong with W213 DRLs

The W213 E-Class features a distinctive LED DRL signature that doubles as the turn signal. Over time, the transparent light guide strip—a component that distributes light from the LED board across the headlight—can develop hot spots, discoloration, or cracks due to thermal stress and UV exposure. The LED board itself may also fail, with individual LEDs burning out or the driver circuit malfunctioning. Common symptoms include uneven illumination, flickering, or a complete loss of the DRL on one side. The failure is usually linked to heat buildup inside the sealed headlight housing, which is why one side often goes before the other.

Diagnosing the Problem

Before ordering parts, confirm the issue is with the DRL guide/LED board and not the headlight control module or wiring. Turn on the DRLs and inspect the glow: if one side is dimmer or has dark spots along the strip, the light guide is likely damaged. If the entire strip is dead but the turn signal (which uses the same strip) works, the LED board's DRL circuit is faulty. A quick test with a multimeter can verify power is reaching the connector. For a definitive diagnosis, compare both sides with the headlights on—if the issue is only in DRL mode, it's not the bulb (there isn't one) but the LED board or guide.

Step-by-Step Replacement Guide

Replacing the DRL light guide and LED board on a W213 is a DIY-friendly job that takes about 2 to 3 hours per side. Here’s how to do it safely:

1. Remove the headlight assembly – Open the hood, disconnect the battery, and unplug the headlight connectors. Remove the upper trim panel and the screws securing the headlight (usually 3-4 bolts). Carefully slide the headlight forward and out.

2. Separate the lens – Place the headlight on a clean bench. Use a heat gun or oven (set to 200°F) to soften the adhesive. Pry the lens off gently using a trim tool. Let it cool slightly.

3. Access the DRL module – The DRL light guide and LED board are located at the top edge of the housing. Remove the screws holding the chrome bezel and the guide assembly.

4. Swap the parts – Carefully unclip the old light guide and detach the LED board from its connector. Install the new guide and board, ensuring they sit flush. Reassemble in reverse order.

5. Seal and test – Apply fresh butyl sealant to the lens groove, press the lens back on, and let it cure. Reinstall the headlight and test the DRLs.

Fitment Tips & Expert Advice

This replacement part is designed for the 2016-2019 W213 models (pre-facelift). For 2020-2023 models, the headlight design changed, so verify compatibility before ordering. When installing, handle the new light guide by its edges to avoid fingerprints, which can cause hotspots. Use lint-free gloves. Most DRL failures on the W213 come down to heat dissipation, so a board with a better thermal path runs cooler and lasts longer than the original. Ensure the foam padding around the board is intact to prevent moisture ingress.

Why Replace with a New Guide & Board?

Replacing just the light guide or LED board individually may seem cost-effective, but they work as a system—a worn guide will still diffuse light poorly, and an aged board may fail soon after. This combined kit ensures optimal light output and color consistency. The replacement board restores original brightness and colour, and the guide is moulded from UV-stabilized acrylic so it resists the yellowing that killed the original. It costs a fraction of the $1,200+ a new assembly would run of a new headlight assembly. For a step-by-step visual, check our installation video on the product page.

FAQ Q: Both W213 E-Class DRLs went dark at the same time - do I need two boards? A: Boards rarely fail simultaneously, so when both sides die together the fault is usually upstream: the DRL fuse, the control module, or the wiring between them. Check the fuse first (the owner's manual lists the slot), then the module. Only replace the boards once the shared parts test fine. Q: There is moisture inside my W213 E-Class headlight - will a new board survive it? A: Not unless you deal with the moisture first. Water ingress is what usually kills the board, so dry the housing completely, replace the butyl seal and check the vent caps, then fit the new board. A cracked lens means the assembly itself is due.

Standards reference: for the Mercedes-Benz W213, the daytime running lamp is governed by UN ECE Regulation 148 (which superseded R87) in most markets and by FMVSS 108 in the United States - these define when the lamp runs and at what output. The replacement parts restore the output those rules were written around.

Q: Can I replace just the LED board without the light guide? A: Yes, but if your guide shows any signs of wear (discoloration, cracks), it's best to replace both to ensure even light distribution.

Q: Will this fit a 2020 W213 facelift model? A: No, the facelift (2020-2023) has a different DRL design. This part is only for 2016-2019 models.

Q: How long does the replacement take? A: For a DIYer, expect 2-3 hours per headlight, including removing the bumper if needed (though not always required).

Q: My DRLs flicker—could it be a wiring issue? A: Flickering is often a sign of a failing LED board. Check the connector for corrosion first; if clean, the board is likely the culprit.

Standards & further reading

Reference material for the standards and technology that govern vehicle lighting equipment:

• FMVSS No. 108 - Lamps, reflective devices, and associated equipment - the US federal standard governing vehicle lighting equipment - ams OSRAM - automotive lighting - light-source and LED technology reference - HELLA - automotive lighting and electronics - vehicle lighting systems reference