What is the low beam headlight bulb size for a 2018 GMC Sierra 3500 HD?

The 2018 GMC Sierra 3500 HD uses a N/A 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 GMC Sierra 3500 HD?

The high beam bulb size for the 2018 GMC Sierra 3500 HD is N/A.

Why are my 2018 GMC Sierra 3500 HD headlights dim?

Dim headlights on a 2018 GMC Sierra 3500 HD can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a N/A LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 2018 GMC Sierra 3500 HD fog light?

The 2018 GMC Sierra 3500 HD uses a H16 bulb for the fog light position.

Is the 2018 GMC Sierra 3500 HD single or dual beam?

The 2018 GMC Sierra 3500 HD uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 2018 GMC Sierra 3500 HD?

Yes, the 2018 GMC Sierra 3500 HD comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a N/A LED conversion kit for the low beams.

Does the 2018 GMC Sierra 3500 HD have fog lights?

Yes, the 2018 GMC Sierra 3500 HD takes a H16 bulb for the fog light position.

Did the 2018 GMC Sierra 3500 HD change headlight bulb sizes from the previous year?

No — the 2018 GMC Sierra 3500 HD uses the same bulb sizes as the 2017 model. This configuration has been consistent across the 2017–2018 generation.

Is the 2018 GMC Sierra 3500 HD the first or last year to use N/A bulbs?

The 2018 GMC Sierra 3500 HD is the last year in the 2017–2018 generation to use the N/A bulb for the low beam headlight.

How do I change the headlight on a 2018 GMC Sierra 3500 HD?

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 N/A bulb counter-clockwise to remove it, then insert the new bulb and reassemble. The whole process typically takes 10 to 30 minutes per side depending on accessibility.

Are LED headlights legal for a 2018 GMC Sierra 3500 HD?

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 N/A 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 GMC Sierra 3500 HD headlights?

A pair of halogen N/A 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 GMC Sierra 3500 HD?

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 N/A position are available as direct plug-and-play replacements.

The 2018 GMC Sierra 3500 HD is the last model year to use this bulb configuration (2017–2018).

Fitment Guaranteed for 2018 GMC Sierra 3500 HD

What Size Bulbs Does a 2018 GMC Sierra 3500 HD Use?

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

Installation Difficulty

Moderate (Dust covers often present)

Est. Replacement Cost

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

What Lighting System Does the 2018 GMC Sierra 3500 HD Have?

The 2018 GMC Sierra 3500 HD utilizes a refined lighting configuration featuring 7 distinct bulb positions. It features a standard lighting system powered by a dual-bulb halogen configuration using separate low beam and high beam bulbs for precise light distribution.

Can You Put LED Bulbs in a 2018 GMC Sierra 3500 HD?

For a GMC built for the road and trail, LED upgrades provide the high-contrast lighting needed for better obstacle detection. We recommend starting your upgrade with the low beams, as they see the most use. Adding a matching LED kit later will complete the look and ensure consistent lighting performance. Don't forget the H16 fog lights; switching these to LED can dramatically improve your visibility in adverse weather.

2018 GMC Sierra 3500 HD Bulb Size Chart

Position	Bulb Size	Shop
Turn Signal Front	7443	Buy 7443 →
Fog Light	H16	Buy H16 →
Parking Light	7443	Buy 7443 →
Side Marker	194	Buy 194 →
License Plate	W5W	Buy W5W →
Reverse Light	921	Buy 921 →
Brake Light	921	Buy 921 →

How do the 2018 GMC Sierra 3500 HD's bulbs compare to other years?

The 2018 GMC Sierra 3500 HD uses the same bulbs as the 2017 model.

The 2019 model switched to a different bulb configuration.

This bulb configuration covers the 2017–2018 model years. ← 2017 2019 →

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Other Sierra 3500 HD Years

2020 2019 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007