What is the low beam headlight bulb size for a 1978 Jaguar XJ12?

The 1978 Jaguar XJ12 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 1978 Jaguar XJ12?

The high beam bulb size for the 1978 Jaguar XJ12 is H5001.

Why are my 1978 Jaguar XJ12 headlights dim?

Dim headlights on a 1978 Jaguar XJ12 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 1978 Jaguar XJ12 fog light?

The 1978 Jaguar XJ12 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 1978 Jaguar XJ12 single or dual beam?

The 1978 Jaguar XJ12 uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 1978 Jaguar XJ12?

Yes, the 1978 Jaguar XJ12 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 1978 Jaguar XJ12 change headlight bulb sizes from the previous year?

Yes — the 1978 Jaguar XJ12 uses different bulb sizes than the 1976 model. The 1978–1979 generation introduced this bulb configuration.

Is the 1978 Jaguar XJ12 the first or last year to use H5006 bulbs?

The 1978 Jaguar XJ12 is the first year in the 1978–1979 generation to use the H5006 bulb for the low beam headlight.

How do I change the headlight on a 1978 Jaguar XJ12?

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 1978 Jaguar XJ12?

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 1978 Jaguar XJ12 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 1978 Jaguar XJ12?

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 1978 Jaguar XJ12 is the first model year to use this bulb configuration (1978–1979).

Fitment Guaranteed for 1978 Jaguar XJ12

What Size Bulbs Does a 1978 Jaguar XJ12 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 1978 Jaguar XJ12 Have?

Lighting on the 1978 Jaguar XJ12 is managed by a total of 4 bulbs, covering everything from primary headlights to signal indicators. 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 XJ12's 1973-1996 production span.

Can You Put LED Bulbs in a 1978 Jaguar XJ12?

Upgrading to LED is one of the most effective ways to modernize your Jaguar'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.

1978 Jaguar XJ12 Bulb Size Chart

Position	Bulb Size	Shop
Turn Signal Front	7528	Buy 7528 →
High Beam	H5001	Buy H5001 →
Low Beam	H5006	Buy H5006 →
Parking Light	7528	Buy 7528 →

How do the 1978 Jaguar XJ12's bulbs compare to other years?

The 1978 Jaguar XJ12 changed bulb sizes from 1976. The previous model year used a different configuration.

The 1979 model continues with the same bulb sizes.

This bulb configuration covers the 1978–1979 model years. ← 1976 1979 →

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Other XJ12 Years

1996 1995 1994 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1976 1975 1974 1973

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