What is the low beam headlight bulb size for a 1966 GMC 3500?

The 1966 GMC 3500 uses a H5006 bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 1966 GMC 3500?

The high beam bulb size for the 1966 GMC 3500 is H5001.

Why are my 1966 GMC 3500 headlights dim?

Dim headlights on a 1966 GMC 3500 can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a H5006 LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 1966 GMC 3500 fog light?

The 1966 GMC 3500 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 1966 GMC 3500 single or dual beam?

The 1966 GMC 3500 uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 1966 GMC 3500?

Yes, the 1966 GMC 3500 comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a H5006 LED conversion kit for the low beams.

Did the 1966 GMC 3500 change headlight bulb sizes from the previous year?

Yes — the 1966 GMC 3500 uses different bulb sizes than the 1965 model. The 1966 generation introduced this bulb configuration.

Is the 1966 GMC 3500 the first or last year to use H5006 bulbs?

The 1966 GMC 3500 is the only year in the 1966 generation to use the H5006 bulb for the low beam headlight.

How do I change the headlight on a 1966 GMC 3500?

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 H5006 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 1966 GMC 3500?

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 H5006 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 1966 GMC 3500 headlights?

A pair of halogen H5006 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 1966 GMC 3500?

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 H5006 position are available as direct plug-and-play replacements.

The 1966 GMC 3500 has a unique bulb configuration not shared with adjacent model years.

Fitment Guaranteed for 1966 GMC 3500

What Size Bulbs Does a 1966 GMC 3500 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 1966 GMC 3500 Have?

When it comes to nighttime visibility, the 1966 GMC 3500 relies on an arrangement of 2 specialized bulbs. It features a standard lighting system powered by a dual-bulb halogen configuration using separate H5006 low beam and H5001 high beam bulbs for precise light distribution. This model belongs to the late years of the 3500's 1960-1966 production span.

Can You Put LED Bulbs in a 1966 GMC 3500?

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 H5006 low beams, as they see the most use. Adding a matching H5001 LED kit later will complete the look and ensure consistent lighting performance.

1966 GMC 3500 Bulb Size Chart

Position	Bulb Size	Shop
Low Beam	H5006	Buy H5006 →
High Beam	H5001	Buy H5001 →

How do the 1966 GMC 3500's bulbs compare to other years?

The 1966 GMC 3500 changed bulb sizes from 1965. The previous model year used a different configuration.

This bulb configuration covers the 1966 model years. ← 1965

Finding the best installation guide...

Other 3500 Years

1965 1964 1963 1962 1961 1960

Other Vehicles That Use H5006 Bulbs

1992 BMW 3 Series 1991 BMW 318i 1991 BMW 325i 1991 BMW 325iX 1991 BMW 325is 1991 Isuzu Impulse