What is the low beam headlight bulb size for a 1988 BMW 635CSi?

The 1988 BMW 635CSi 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 1988 BMW 635CSi?

The high beam bulb size for the 1988 BMW 635CSi is H5001.

Why are my 1988 BMW 635CSi headlights dim?

Dim headlights on a 1988 BMW 635CSi 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 1988 BMW 635CSi fog light?

The 1988 BMW 635CSi uses a H1 bulb for the fog light position.

Is the 1988 BMW 635CSi single or dual beam?

The 1988 BMW 635CSi uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 1988 BMW 635CSi?

Yes, the 1988 BMW 635CSi 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.

Does the 1988 BMW 635CSi have fog lights?

Yes, the 1988 BMW 635CSi takes a H1 bulb for the fog light position.

Did the 1988 BMW 635CSi change headlight bulb sizes from the previous year?

Yes — the 1988 BMW 635CSi uses different bulb sizes than the 1987 model. The 1988 generation introduced this bulb configuration.

Is the 1988 BMW 635CSi the first or last year to use H5006 bulbs?

The 1988 BMW 635CSi is the only year in the 1988 generation to use the H5006 bulb for the low beam headlight.

How do I change the headlight on a 1988 BMW 635CSi?

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. Note: BMW vehicles use a CANbus system, so LED replacements may need an anti-flicker decoder. The whole process typically takes 10 to 30 minutes per side depending on accessibility.

Are LED headlights legal for a 1988 BMW 635CSi?

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 1988 BMW 635CSi 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 1988 BMW 635CSi?

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. Since the BMW uses CANbus monitoring, choose a CANbus-compatible LED kit to avoid dashboard errors.

The 1988 BMW 635CSi has a unique bulb configuration not shared with adjacent model years.

Fitment Guaranteed for 1988 BMW 635CSi

What Size Bulbs Does a 1988 BMW 635CSi Use?

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

Installation Difficulty

Hard (Tight clearances)

Est. Replacement Cost

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

What Lighting System Does the 1988 BMW 635CSi Have?

Owners of the 1988 BMW 635CSi will find a total of 6 lighting elements throughout the vehicle's exterior. 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 635CSi's 1985-1989 production span. Note that BMW vehicles typically feature a CANbus electrical monitor that checks for specific bulb resistance.

LED Flicker Warning

This vehicle is known to use a CANbus system. Installing standard LEDs may cause flickering.

Use a CANbus decoder.

Can You Put LED Bulbs in a 1988 BMW 635CSi?

Upgrading to LED is one of the most effective ways to modernize your BMW'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. Because BMW utilizes a CANbus system, standard LED bulbs may cause "bulb out" errors on your dashboard. Always opt for "Error-Free" or CANbus-ready kits which include the necessary resistors. Don't forget the H1 fog lights; switching these to LED can dramatically improve your visibility in adverse weather.

1988 BMW 635CSi Bulb Size Chart

Position	Bulb Size	Shop
High Beam	H5001	Buy H5001 →
Side Marker	W5W	Buy W5W →
Low Beam	H5006	Buy H5006 →
Turn Signal Front	7528	Buy 7528 →
Fog Light	H1	Buy H1 →
Parking Light	7528	Buy 7528 →

How do the 1988 BMW 635CSi's bulbs compare to other years?

The 1988 BMW 635CSi changed bulb sizes from 1987. The previous model year used a different configuration.

The 1989 model switched to a different bulb configuration.

This bulb configuration covers the 1988 model years. ← 1987 1989 →

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Other 635CSi Years

1989 1987 1985

Other Vehicles That Use H5006 Bulbs

1991 Isuzu Impulse 1989 Jaguar Vanden Plas 1989 Jaguar XJ12 1989 Jaguar XJ6 1989 Jaguar XJS 1988 Ferrari Testarossa