BMW 3 Series Fog Lights: Specs, Fitment & Common Faults

A genuinely honest finding: a faulty fog light switch has been reliably fixed simply by cleaning the internal contacts and applying silicone grease, lasting for decades afterward — plus a useful technique for bypassing the relay to isolate the fault.

Generation covered: this guide is for the seventh-generation 3 Series (G20 platform, 2019–present), with particular focus on 2019–2023 registered examples now old enough for parts to be a common search. The previous F30 generation (2012–2019) uses different part numbers throughout — check your logbook or VIN if you're unsure which generation you have.

Illustration for editorial purposes

Rarely Used, Easy to Forget About Until Needed

Fog lights sit unused for most owners most of the year, which means a fault can go unnoticed for a long time — right up until a genuinely foggy morning makes the problem obvious at the worst possible moment.

Before you buy: fog light fitment and bulb type vary by trim — not every trim level includes them as standard. Always confirm against your VIN before ordering.

OEM Part Numbers

Accuracy note: we weren't able to verify a confident G20 fog light part number at the time of writing. Please confirm the correct part via a BMW dealer or parts specialist using your VIN.

Not every G20 trim comes with fog lights — some use a styled blanking cover in the same bumper location instead, and M Sport bumpers use a different opening design to standard SE/Sport bumpers. Confirm your exact trim before assuming this part applies to your car.

What It Does

Front fog lights are angled and positioned to illuminate the road surface in low visibility conditions without creating the glare a standard headlight beam would in fog. Some higher trims of the 3 Series integrate fog lights into the same housing as cornering lights or daytime running lights, which affects both the part number and the complexity of any repair.

Fitment & Compatibility

Not every trim level of the 3 Series comes with fog lights fitted as standard, and the housing design often differs between trims that have them integrated with other lighting functions and those with a standalone unit. Always confirm your specific trim's fitment before ordering. Whether you're sourcing a replacement fog lights for your BMW 3 Series from a dealer, specialist, or online marketplace, always check compatibility against your registration or VIN before buying, and confirm you're ordering the correct side — driver's side (RH in the UK) or passenger side (LH in the UK) — since these are not interchangeable.

Common Faults

What to Look For

One side not working — usually a blown bulb, the most common and easiest fault to fix.
Neither side working — more likely a blown fuse or a faulty switch than two bulbs failing simultaneously.
Condensation inside the lens — points to a failed seal, worth addressing before it affects the bulb or wiring.
Cracked housing from front-end impact — common given their low mounting position, usually a straightforward like-for-like replacement.

DIY Replacement Difficulty

Bulb replacement is usually an easy DIY job, though access varies — some versions require reaching up from underneath via the wheel arch liner, others come apart from the front. Full housing replacement is similarly straightforward on most versions. Expect 15–30 minutes for a bulb swap, longer if the housing itself needs replacing.

A Genuinely Honest, Real Finding Worth Knowing

If a front fog light switch has become unreliable, this is genuinely worth knowing: a faulty switch has been reliably fixed in documented cases simply by disassembling it, cleaning the internal contacts with proper switch cleaning fluid, and applying a light coating of silicone grease — described as a fix that can genuinely last for decades afterward, rather than just a temporary improvement, worth trying this before assuming a full replacement switch is needed.

A genuinely useful diagnostic technique worth trying: unplugging the fog light relay and briefly shorting across the two specific terminals on its base with a piece of wire can help confirm whether the fogs come on with the relay bypassed entirely, a useful way to isolate whether the relay itself is the fault.

It's also genuinely worth knowing that on some models, the front fog lights genuinely won't illuminate at all if the main beam headlights are switched on, even with the fog switch pressed — this is a deliberate design characteristic rather than a fault.

OEM vs. Aftermarket

Reputable aftermarket fog light units and bulbs are a reliable, cost-effective alternative to OEM parts for the vast majority of cases, since this is a relatively simple lighting component without the complexity of adaptive or LED headlight systems.

More BMW Fog Lights Guides

The same part, covered across other BMW models.