What is the low beam headlight bulb size for a 2018 Mercedes-Benz GLS550?

The 2018 Mercedes-Benz GLS550 uses a H7 bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 2018 Mercedes-Benz GLS550?

The high beam bulb size for the 2018 Mercedes-Benz GLS550 is H7.

Why are my 2018 Mercedes-Benz GLS550 headlights dim?

Dim headlights on a 2018 Mercedes-Benz GLS550 can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a H7 LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 2018 Mercedes-Benz GLS550 fog light?

The 2018 Mercedes-Benz GLS550 typically does not come with factory fog lights in all trim levels. If your vehicle is equipped with them, check the manual as sizes can vary by trim.

Is the 2018 Mercedes-Benz GLS550 single or dual beam?

The 2018 Mercedes-Benz GLS550 uses a single bulb (dual filament) headlight system. This means one bulb controls both high and low beams.

Can I install LED bulbs on my 2018 Mercedes-Benz GLS550?

Yes, the 2018 Mercedes-Benz GLS550 comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a H7 LED conversion kit for the low beams.

Did the 2018 Mercedes-Benz GLS550 change headlight bulb sizes from the previous year?

No — the 2018 Mercedes-Benz GLS550 uses the same bulb sizes as the 2017 model. This configuration has been consistent across the 2017–2018 generation.

Is the 2018 Mercedes-Benz GLS550 the first or last year to use H7 bulbs?

The 2018 Mercedes-Benz GLS550 is the last year in the 2017–2018 generation to use the H7 bulb for the low beam headlight.

How do I change the headlight on a 2018 Mercedes-Benz GLS550?

Turn off the vehicle and open the hood. Locate the headlight assembly from behind, remove the dust cover or retaining clip, disconnect the wiring harness, twist the old H7 bulb counter-clockwise to remove it, then insert the new bulb and reassemble. Note: Mercedes-Benz vehicles use a CANbus system, so LED replacements may need an anti-flicker decoder. The whole process typically takes 10 to 30 minutes per side depending on accessibility.

Are LED headlights legal for a 2018 Mercedes-Benz GLS550?

LED bulbs used off-road or in auxiliary lights are legal everywhere. For on-road headlight use, legality varies by state. Many states allow LED retrofits as long as the beam pattern meets DOT standards. For the best legal compliance, choose a DOT-approved H7 LED kit that is designed as a direct replacement and produces a proper cutoff pattern without excessive glare.

How much does it cost to replace 2018 Mercedes-Benz GLS550 headlights?

A pair of halogen H7 bulbs costs $15 to $40, while LED conversion kits run $25 to $60 per pair. If you have a shop do the work, expect an additional $20 to $50 in labor per bulb. Replacing them yourself at home saves the labor cost and usually takes under 30 minutes.

What is the difference between halogen and LED for a 2018 Mercedes-Benz GLS550?

Halogen bulbs produce a warm yellow light (around 3200K), last 500 to 1000 hours, and draw more power. LED bulbs emit a brighter white light (5000-6000K), last 25,000+ hours, and use less energy. LED upgrades for the H7 position are available as direct plug-and-play replacements. Since the Mercedes-Benz uses CANbus monitoring, choose a CANbus-compatible LED kit to avoid dashboard errors.

The 2018 Mercedes-Benz GLS550 is the last model year to use this bulb configuration (2017–2018).

Fitment Guaranteed for 2018 Mercedes-Benz GLS550

What Size Bulbs Does a 2018 Mercedes-Benz GLS550 Use?

Correct headlight, fog light, and tail light bulb sizes. Sourced from OEM catalog data.

Installation Difficulty

Hard (Tight clearances)

Est. Replacement Cost

$15 - $40 (Halogen) / $30+ (LED)

What Lighting System Does the 2018 Mercedes-Benz GLS550 Have?

Owners of the 2018 Mercedes-Benz GLS550 will find a total of 3 lighting elements throughout the vehicle's exterior. It features a standard lighting system powered by a halogen-based setup where a single H7 dual-filament bulb handles both low and high beam duties within the same reflector. This model belongs to the mid years of the GLS550's 2017-2019 production span. Note that Mercedes-Benz vehicles typically feature a CANbus electrical monitor that checks for specific bulb resistance.

LED Flicker Warning

This vehicle is known to use a CANbus system. Installing standard LEDs may cause flickering.

Use a CANbus decoder.

Can You Put LED Bulbs in a 2018 Mercedes-Benz GLS550?

Upgrading to LED is one of the most effective ways to modernize your Mercedes-Benz's appearance and safety profile. Since your GLS550 uses a single H7 bulb for both high and low beams, ensure your chosen LED kit is "dual-beam" compatible. This allows the LED circuitry to mimic the two-filament design of the original halogen bulb. Because Mercedes-Benz utilizes a CANbus system, standard LED bulbs may cause "bulb out" errors on your dashboard. Always opt for "Error-Free" or CANbus-ready kits which include the necessary resistors.