What is the low beam headlight bulb size for a 2017 BMW 340i?

The 2017 BMW 340i 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 2017 BMW 340i?

The high beam bulb size for the 2017 BMW 340i is H7 LED.

Why are my 2017 BMW 340i headlights dim?

Dim headlights on a 2017 BMW 340i 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 2017 BMW 340i fog light?

The 2017 BMW 340i uses a H8 LED bulb for the fog light position.

Is the 2017 BMW 340i single or dual beam?

The 2017 BMW 340i 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 2017 BMW 340i?

Yes, the 2017 BMW 340i 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 2017 BMW 340i have fog lights?

Yes, the 2017 BMW 340i takes a H8 LED bulb for the fog light position.

Did the 2017 BMW 340i change headlight bulb sizes from the previous year?

Yes — the 2017 BMW 340i uses different bulb sizes than the 2016 model. The 2017–2018 generation introduced this bulb configuration.

Is the 2017 BMW 340i the first or last year to use H7 LED bulbs?

The 2017 BMW 340i is the first year in the 2017–2018 generation to use the H7 LED bulb for the low beam headlight.

How do I change the headlight on a 2017 BMW 340i?

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 2017 BMW 340i?

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 2017 BMW 340i 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 2017 BMW 340i?

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.

The 2017 BMW 340i is the first model year to use this bulb configuration (2017–2018).

Fitment Guaranteed for 2017 BMW 340i

What Size Bulbs Does a 2017 BMW 340i 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 2017 BMW 340i Have?

The 2017 BMW 340i utilizes a refined lighting configuration featuring 13 distinct bulb positions. 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. This model belongs to the mid years of the 340i's 2016-2018 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 2017 BMW 340i?

Upgrading to LED is one of the most effective ways to modernize your BMW's appearance and safety profile. Since your 340i 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.

2017 BMW 340i 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 →

How do the 2017 BMW 340i's bulbs compare to other years?

The 2017 BMW 340i changed bulb sizes from 2016. The previous model year used a different configuration.

The 2018 model continues with the same bulb sizes.

This bulb configuration covers the 2017–2018 model years. ← 2016 2018 →

Finding the best installation guide...

Other 340i Years

2018 2016

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