Citroen C4 Fog Lights: Specs, Fitment & Common Faults

A genuinely important fact: correct wiring alone isn't enough — the BSI must be specifically coded to enable front fogs, plus a genuine, distinct fault where fogs turn on by themselves.

Generation covered: this guide is for the current C4 (launched 2021, facelifted 2024), with particular focus on 2021–2023 registered examples now old enough for parts to be a common search. Check your logbook or VIN if you're unsure which generation you have.

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A Genuinely Important Fact: Correct Wiring Alone Isn't Enough

If you're retrofitting front fog lights, or troubleshooting fogs that don't respond despite everything appearing correctly wired, this is genuinely worth knowing: the BSI (the car's central electrical control module) must be specifically told via diagnostic software that front fog lights are fitted, even when the physical wiring, relay, fuse, and switch are all genuinely present and correctly connected. Without this specific coding step (accessible through DiagBox under manual configuration and car options), the BSI simply won't activate the fogs regardless of how correctly everything else has been wired — a completely different issue from a wiring fault, and one that basic electrical troubleshooting alone won't fix.

A genuine, distinct fault worth knowing about — fogs turning on by themselves: one documented owner reported front and rear fog lights occasionally activating on their own, either staying on or flickering, specifically when the headlights were switched on, with the switch itself having no effect on stopping it. This is worth knowing as a genuine, real fault pattern distinct from fogs simply failing to work — worth mentioning specifically to an auto-electrician if you experience this, since it points toward a stuck relay or a BSI communication fault rather than a simple bulb or switch issue.

It's also worth knowing that fogs on this platform, like on related Stellantis models, are frequently controlled without a conventional dedicated fuse listed in the handbook at all — if you've searched the fuse box diagram thoroughly and found nothing specifically for fog lights, this may genuinely be correct rather than something you've missed.

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 C4-specific fog light part number at the time of writing. Please confirm the correct part via a Citroen dealer or parts specialist using your VIN.

Not every C4 trim comes with front fog lights — some use a styled blanking cover in the same bumper location instead. 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 C4 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

Generations & Fog Light Type

Standard trims	Halogen fog light bulb as standard
Higher trims, later model years	LED fog lights become available further up the range, genuinely a different assembly and connector from the halogen units on lower trims

Not every trim level of the C4 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 Citroen C4 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, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Fog Lights Guide for common faults to check for (including exactly what fails an MOT), how easy this job is to DIY, and aftermarket advice.

More Citroen Fog Lights

The same part, covered across other Citroen models.

Citroen C4 Fog Lights: Specs, Fitment & Common Faults

A Genuinely Important Fact: Correct Wiring Alone Isn't Enough

OEM Part Numbers

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