What is the low beam headlight bulb size for a 2018 BMW 340i xDrive?

The 2018 BMW 340i xDrive uses a H7 LED bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 2018 BMW 340i xDrive?

The high beam bulb size for the 2018 BMW 340i xDrive is H7 LED.

Why are my 2018 BMW 340i xDrive headlights dim?

Dim headlights on a 2018 BMW 340i xDrive can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a H7 LED LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 2018 BMW 340i xDrive fog light?

The 2018 BMW 340i xDrive uses a H8 LED bulb for the fog light position.

Is the 2018 BMW 340i xDrive single or dual beam?

The 2018 BMW 340i xDrive uses a single bulb (dual filament) headlight system. This means one bulb controls both high and low beams.

Can I install LED bulbs on my 2018 BMW 340i xDrive?

Yes, the 2018 BMW 340i xDrive comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a H7 LED LED conversion kit for the low beams.

Does the 2018 BMW 340i xDrive have fog lights?

Yes, the 2018 BMW 340i xDrive takes a H8 LED bulb for the fog light position.

How do I change the headlight on a 2018 BMW 340i xDrive?

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 H7 LED 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 2018 BMW 340i xDrive?

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 H7 LED 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 2018 BMW 340i xDrive headlights?

A pair of halogen H7 LED 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 2018 BMW 340i xDrive?

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 H7 LED 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.

This vehicle is part of the 2017–2018 BMW 340i xDrive generation. All models in this range share identical light bulb sizes.

Fitment Guaranteed for 2018 BMW 340i xDrive

What Size Bulbs Does a 2018 BMW 340i xDrive 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 2018 BMW 340i xDrive Have?

Owners of the 2018 BMW 340i xDrive will find a total of 13 lighting elements throughout the vehicle's exterior. It features an extensive lighting system powered by a halogen-based setup where a single H7 LED dual-filament bulb handles both low and high beam duties within the same reflector. 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 2018 BMW 340i xDrive?

Upgrading to LED is one of the most effective ways to modernize your BMW's appearance and safety profile. Since your 340i xDrive uses a single H7 LED bulb for both high and low beams, ensure your chosen LED kit is "dual-beam" compatible. This allows the LED circuitry to mimic the two-filament design of the original halogen bulb. 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 H8 LED fog lights; switching these to LED can dramatically improve your visibility in adverse weather.

2018 BMW 340i xDrive Bulb Size Chart

Position	Bulb Size	Shop
Low Beam	H7 LED	Buy H7 LED →
High Beam	H7 LED	Buy H7 LED →
Fog Light	H8 LED	Buy H8 LED →
Brake Light	LED Bulb	Buy LED Bulb →
Side Marker	LED Bulb	Buy LED Bulb →
Turn Signal Front	3457NA LED	Buy 3457NA LED →
Turn Signal Rear	LED Bulb	Buy LED Bulb →
Dome Light	2825	Buy 2825 →
License Plate	LED Bulb	Buy LED Bulb →
Map Light	LED Bulb	Buy LED Bulb →
Parking Light	3457NA	Buy 3457NA →
Reverse Light	LED Bulb	Buy LED Bulb →
Trunk Light	LED Light	Buy LED Light →