What is the low beam headlight bulb size for a 1966 Mercury S-55?

The 1966 Mercury S-55 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 Mercury S-55?

The high beam bulb size for the 1966 Mercury S-55 is H5001.

Why are my 1966 Mercury S-55 headlights dim?

Dim headlights on a 1966 Mercury S-55 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 Mercury S-55 fog light?

The 1966 Mercury S-55 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 Mercury S-55 single or dual beam?

The 1966 Mercury S-55 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 Mercury S-55?

Yes, the 1966 Mercury S-55 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.

How do I change the headlight on a 1966 Mercury S-55?

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 Mercury S-55?

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 Mercury S-55 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 Mercury S-55?

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 Mercury S-55 is the first model year to use this bulb configuration (1966–1967).

Fitment Guaranteed for 1966 Mercury S-55

What Size Bulbs Does a 1966 Mercury S-55 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 Mercury S-55 Have?

When it comes to nighttime visibility, the 1966 Mercury S-55 relies on an arrangement of 7 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 early years of the S-55's 1966-1967 production span.

Can You Put LED Bulbs in a 1966 Mercury S-55?

Upgrading to LED is one of the most effective ways to modernize your Mercury's appearance and safety profile. 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 Mercury S-55 Bulb Size Chart

Position	Bulb Size	Shop
High Beam	H5001	Buy H5001 →
Low Beam	H5006	Buy H5006 →
Turn Signal Front	1157A	Buy 1157A →
Brake Light	1157	Buy 1157 →
Turn Signal Rear	1157	Buy 1157 →
Tail Light	1157	Buy 1157 →
Parking Light	1157A	Buy 1157A →

How do the 1966 Mercury S-55's bulbs compare to other years?

The 1967 model continues with the same bulb sizes.

This bulb configuration covers the 1966–1967 model years. 1967 →

Finding the best installation guide...

Other S-55 Years

1967

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