A dealer will charge you €60–100 ($65–110) to replace a headlight bulb that costs €8–15 ($9–16) for a decent branded pair. The labour is often five minutes. This is the single best-value repair in car ownership, and it's the last stop on the Weekend DIYer path for a reason: bulbs and fuses are where most people first discover that the car isn't magic.

Fifteen minutes, no jack, no torque wrench. Here's the whole job — including the parts nobody tells you about.

Know your bulb before you buy

Headlight bulbs come in standardised fittings, and they are not interchangeable. The common ones:

  • H7 — the default European low beam for roughly the last 25 years. Single filament, 55W.
  • H4 — combined low and high beam in one bulb (twin filament). Common on older and smaller cars.
  • H1 — older low/high beam and many fog lights. Looks vaguely like an H7 in photos. Isn't one.
  • H11 — fog lights and some low beams, especially on Asian and American cars.
  • HB3 (9005) / HB4 (9006) — high beam and low beam respectively on many US and Japanese models.

Your owner's manual has a bulb chart listing every position — low beam, high beam, indicators, brake lights — with the exact fitting and wattage. Use it. If the manual's gone, pull the old bulb and read the code stamped on the metal base, or run your registration through the Osram or Philips online bulb finder.

Buy the right fitting, buy a known brand, and buy two. A standard H7 pair runs €8–15 ($9–16); a performance pair (Osram Night Breaker, Philips RacingVision) €25–40 ($27–44). The performance bulbs are genuinely brighter but live shorter lives. Pick your trade-off knowingly.

Never touch the glass

This is the rule that separates a bulb lasting two years from one lasting two months.

Halogen bulbs run their quartz envelope at several hundred degrees Celsius. Oil from your fingertips doesn't wipe off in service — it bakes into the quartz and creates a hot spot. The glass weakens there, the bulb fails early, sometimes the envelope bulges or cracks. That "faulty" bulb you returned? You killed it during installation.

Handle bulbs by the metal base only. Wear nitrile gloves or use the cardboard sleeve it ships in. If you slip and touch the glass, clean it with isopropyl alcohol on a lint-free cloth before fitting. Ten seconds of care doubles the bulb's life.

Replace them in pairs

Halogen filaments degrade together. Tungsten evaporates off the filament over hundreds of hours of use and darkens the envelope; a three-year-old bulb can be down 30% on output while still technically "working." Fit one fresh bulb and you'll have one white eye and one yellow one — annoying at best, and a mismatched beam at worst.

The second bulb costs a few euros. The other one is weeks from failing anyway. Do both, log the job, done.

Check access before you buy anything

Here's the part the ten-minute YouTube video skips: on some cars, the bulb is the easy part and reaching it is the job.

  • Best case: open the bonnet, pop a rubber dust cap off the back of the headlight, release a wire clip, swap the bulb. Five minutes per side.
  • Common annoyance: the battery, air box, or washer bottle blocks one side. You'll work blind by feel, or remove a component. Add 20 minutes and some swearing.
  • Wheel-arch route: some cars (plenty of superminis) give access through a flap in the wheel-arch liner. Turn the wheel to full lock, pop the flap, work through the hole.
  • The horror stories: certain models require removing the bumper or the entire headlight unit to change a bulb. A front-end panel-off bulb change at a workshop can legitimately cost an hour of labour — this is where the €80 invoice actually comes from.

So before you order bulbs: open the bonnet, look behind the headlight, and see what you're dealing with. Five minutes of checking tells you whether this is a driveway job or a Saturday-morning job. Either way it's still cheaper than the dealer — you just want to know before the old bulb dies on a Sunday night.

LED retrofits: the honest paragraph

You've seen the €30 H7-LED kits promising "300% more light." Here's the situation in the EU: a generic LED bulb in a housing type-approved for halogen has no ECE approval and is not road legal. The optics of a halogen reflector are designed around a filament in a precise position; an LED chip in roughly the same place scatters light differently, usually dazzling oncoming traffic even when it looks fine from the driver's seat. Fitting one means a failed periodic inspection (TÜV, MOT, contrôle technique) and — the part that should worry you — a potential insurance problem after a night-time crash, because the vehicle no longer matched its type approval.

The legitimate exceptions: Osram (Night Breaker LED) and Philips (Ultinon Pro6000) have pushed specific retrofit LEDs through national approval processes. These are legal only in certain countries (Germany was first, others followed), only on vehicles listed in the manufacturer's official compatibility list, and in some cases only if you carry the approval certificate in the car. Approval is per headlight design, not per bulb — that's why the lists exist. If your exact car and headlamp are on the Osram or Philips list for your country, an approved retrofit at €90–130 ($100–145) a pair is a genuine, legal upgrade. If it isn't, there is no legal LED option for that housing. Full stop.

The US is looser in enforcement but not in law: FMVSS 108 requires headlamps to meet spec as a system, and no LED retrofit in a halogen housing is federally compliant. States rarely check. Europe does.

Xenon and full-LED cars: know when to stop

If your car has factory xenon (HID), the bulb (D1S, D2S, etc.) is fed by a ballast producing up to 25,000 volts at ignition. Bulbs cost €40–80 ($44–88) each and replacement is DIY-possible, but: battery disconnected, lights off for several minutes to discharge, and if the access is buried, honestly consider paying someone. This is the one bulb job where the electricity can hurt you.

If your car has full-LED headlights, there is no bulb. The LEDs are integrated into the assembly, and when a section fails you replace the whole unit — €300–1,000 ($330–1,100) for a basic LED lamp, and matrix-LED units on premium cars can clear €1,500 ($1,650). This is why a cracked headlight from a stone is now an insurance conversation, and why it's worth checking what your car actually has before assuming any of this article's bulb advice applies.

Fuses: the other 15-minute fix

A light that's dead on one side is usually a bulb. Dead on both sides, or a whole function gone — horn, wipers, 12V socket — is usually a fuse.

Your car has at least two fuse boxes: one in the engine bay (high-current stuff) and one in the cabin, typically behind a panel under the dashboard or at the end of the dash, visible with the driver's door open. The lid — or the manual — carries a diagram mapping each numbered slot to a circuit and rating.

Modern cars use blade fuses in three sizes: mini, standard (ATO), and maxi, with the rating printed on top and colour-coded (red 10A, blue 15A, yellow 20A, and so on). Two ways to find the dead one:

  • Pull and look. Use the fuse puller clipped inside the box, hold the fuse to the light, and check the wire bridge inside. Melted gap = blown. Works, but slow if you're hunting.
  • Test light or multimeter. Most blade fuses have two exposed test points on top. Probe both with a test light, ignition on: power on both sides means good, power on one side means blown. No pulling, ten seconds per fuse. (If the words "test light" are new, read our car electrical systems guide first — it covers circuits, grounds, and how to use a multimeter without guessing.)

Replace with the same rating. Always. The fuse isn't protecting the headlight — it's protecting the wire feeding it. A 10A circuit is wired with copper sized for about that current. Fit a 15A fuse and the wire becomes the fuse: it heats, the insulation melts, and the failure moves from a €0.20 part in a plastic box to a loom buried in the dashboard. Up-rating a fuse is how electrical fires start.

And if the new fuse blows immediately, or again next week? The circuit is telling you it has a short — chafed insulation grounding out, water in a connector, a seizing motor. Find the fault. Feeding it fuses just schedules the failure for somewhere darker and further from home.

Relays and the swap-test trick

Next to the fuses you'll find relays — small cubes that let a low-current switch control a high-current circuit. When one fails, the circuit dies even though its fuse is fine.

The classic diagnostic costs nothing: many relays in the same box are identical part numbers. Suspect the horn relay? Swap it with the matching relay from an unimportant circuit (rear demister, say). Horn works now? Failed relay, €10–15 ($11–16). Still dead? Problem's elsewhere. Thirty seconds, zero tools, and it's the same logic professionals use before reaching for a wiring diagram.

The €5 insurance policy

Keep a blade fuse assortment in the glovebox — €5–10 ($6–11) buys 100+ fuses in mini and standard sizes, 5A to 30A. A blown fuse at night, in the rain, 200 km from home goes from "call recovery" to a two-minute fix. Many EU countries formally require carrying spare bulbs anyway (France recommends it; some countries can fine you at a roadside check if a light is out and you can't fix it) — a spare bulb kit for your fittings costs €15–20 ($16–22) and lives next to the fuses.

Log every bulb and fuse in GarageHub with date and mileage. When the same fuse blows twice in six months, the record is what turns "weird coincidence" into "there's a short in that circuit" — and that's a diagnosis you walk into a workshop with, instead of a mystery you pay them to rediscover.