What is the low beam headlight bulb size for a 2003 GMC Sierra 2500 HD?

The 2003 GMC Sierra 2500 HD uses a 9006 bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 2003 GMC Sierra 2500 HD?

The high beam bulb size for the 2003 GMC Sierra 2500 HD is 9005.

Why are my 2003 GMC Sierra 2500 HD headlights dim?

Dim headlights on a 2003 GMC Sierra 2500 HD can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a 9006 LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 2003 GMC Sierra 2500 HD fog light?

The 2003 GMC Sierra 2500 HD uses a H10 bulb for the fog light position.

Is the 2003 GMC Sierra 2500 HD single or dual beam?

The 2003 GMC Sierra 2500 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 2003 GMC Sierra 2500 HD?

Yes, the 2003 GMC Sierra 2500 HD comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a 9006 LED conversion kit for the low beams.

Does the 2003 GMC Sierra 2500 HD have fog lights?

Yes, the 2003 GMC Sierra 2500 HD takes a H10 bulb for the fog light position.

Did the 2003 GMC Sierra 2500 HD change headlight bulb sizes from the previous year?

Yes — the 2003 GMC Sierra 2500 HD uses different bulb sizes than the 2002 model. The 2003 generation introduced this bulb configuration.

Is the 2003 GMC Sierra 2500 HD the first or last year to use 9006 bulbs?

The 2003 GMC Sierra 2500 HD is the only year in the 2003 generation to use the 9006 bulb for the low beam headlight.

How do I change the headlight on a 2003 GMC Sierra 2500 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 9006 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 2003 GMC Sierra 2500 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 9006 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 2003 GMC Sierra 2500 HD headlights?

A pair of halogen 9006 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 2003 GMC Sierra 2500 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 9006 position are available as direct plug-and-play replacements.

The 2003 GMC Sierra 2500 HD has a unique bulb configuration not shared with adjacent model years.

Fitment Guaranteed for 2003 GMC Sierra 2500 HD

What Size Bulbs Does a 2003 GMC Sierra 2500 HD Use?

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

Installation Difficulty

Easy (Plug and Play)

Est. Replacement Cost

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

What Lighting System Does the 2003 GMC Sierra 2500 HD Have?

Owners of the 2003 GMC Sierra 2500 HD will find a total of 13 lighting elements throughout the vehicle's exterior. It features an extensive lighting system powered by a dual-bulb halogen configuration using separate 9006 low beam and 9005 high beam bulbs for precise light distribution.

Can You Put LED Bulbs in a 2003 GMC Sierra 2500 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 9006 low beams, as they see the most use. Adding a matching 9005 LED kit later will complete the look and ensure consistent lighting performance. Don't forget the H10 fog lights; switching these to LED can dramatically improve your visibility in adverse weather.

2003 GMC Sierra 2500 HD Bulb Size Chart

Position	Bulb Size	Shop
Turn Signal Front	3157NA	Buy 3157NA →
Daytime Running	3157CK	Buy 3157CK →
Low Beam	9006	Buy 9006 →
High Beam	9005	Buy 9005 →
Fog Light	H10	Buy H10 →
Side Marker	194	Buy 194 →
Tail Light	3157CK	Buy 3157CK →
License Plate	194	Buy 194 →
Parking Light	3157NA	Buy 3157NA →
Reverse Light	3157CK	Buy 3157CK →
Brake Light	3157CK	Buy 3157CK →
Turn Signal Rear	3157	Buy 3157 →
Map Light	168	Buy 168 →

How do the 2003 GMC Sierra 2500 HD's bulbs compare to other years?

The 2003 GMC Sierra 2500 HD changed bulb sizes from 2002. The previous model year used a different configuration.

The 2004 model switched to a different bulb configuration.

This bulb configuration covers the 2003 model years. ← 2002 2004 →

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Other Sierra 2500 HD Years

2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2002 2001

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9006 Comparisons

9005 vs 9006 9006 vs H11 9006 vs HB4