How to change a headlight bulb: a step-by-step guide

On many cars it's a quick job with no tools. On some, the headlight is hard to reach and needs parts removed, and on cars with xenon or factory LED headlights it isn't a job for the driveway at all.

Before you start: is your headlight a replaceable bulb?

This guide covers halogen headlight bulbs, the most common type. Check yours first:

• Halogen (codes such as H7, H4, H1, H11, HB3, H15): replaceable at home on most cars.
• Xenon (HID): uses a high-voltage igniter. Leave it to a garage.
• Factory LED: often not a bulb at all. The light source is part of the headlight unit and isn't replaced as a bulb.

Of the 360 UK car generations where we've verified the dipped beam, 201 use an H7, 74 an H4, 20 an H11, and 43 have factory LED units that aren't replaceable as bulbs. If you're not sure which you have, see halogen, xenon or LED: how to tell.

Fitting LED or HID bulbs into a halogen headlight unit is not the answer to a failed bulb either: under the MOT inspection manual (section 4.1.4), that conversion is a fail on cars first used on or after 1 April 1986. Our guide to LED headlight bulbs and the law explains why.

Which headlight bulb do I need?

Get the exact code for your car before you start. The common halogen types aren't interchangeable, because each has a different base:

Some cars use one type for both beams; others use two. The Ford Fiesta Mk7 uses H7 dipped and H1 main; the Nissan Juke F15 uses a single H4 for both; the Kia Sportage QL uses HB3 for both. Our guide to H7 vs H4 vs H1 covers the differences.

How to change a headlight bulb, step by step

Check your handbook's bulb-changing section first, because access differs from car to car. The general method for a halogen bulb:

1. Switch off. Turn off the lights and the ignition and take the key out or switch the car fully off. If the lights have been on, let the bulb cool; halogen bulbs get very hot. If you've just driven, let the engine bay cool too.
2. Open the bonnet and find the back of the headlight. Look for a round rubber or plastic dust cover behind the headlight. On some cars there are separate covers for dipped and main beam.
3. Unplug the connector. Pull the wiring plug straight off the back of the bulb. Don't pull on the wires themselves. On some cars the plug sits under the dust cover, so do step 4 first.
4. Remove the dust cover. Pull it off or twist it anticlockwise, depending on the design.
5. Release the bulb. Many halogen headlights use a wire spring clip: press it in and sideways to unhook it, then swing it out of the way. Others use a holder you twist to release. Note how the old bulb sits, especially the position of the tabs on its base.
6. Take out the old bulb. Lift it straight out. Compare it with the new one to make sure the code and base match.
7. Fit the new bulb without touching the glass. Hold it by the base only. Line up the tabs with the slots so it sits flat, then refit the clip or twist the holder until it locks.
8. Refit the dust cover and connector. Make sure the cover seals all round. A gap lets in moisture, which can mist the headlight.
9. Test. Switch on dipped beam, then main beam, and check both sides. Check the front sidelights and indicators while you're there.

If you do touch the glass, clean it with a lint-free cloth and a little isopropyl alcohol before fitting.

Why is it so hard to reach the headlight bulb on my car?

On many cars there's plenty of room behind the headlight. On others, the battery, air filter box or coolant bottle sits in the way, or the handbook tells you to reach in through an access panel in the wheel arch liner. A few designs require the front bumper or headlight unit to be removed.

If the handbook says the job needs the bumper off, or you can't reach the bulb without forcing anything, a garage is the sensible option. Breaking a headlight clip or a bumper fixing turns a simple job into an expensive one.

Do I need to check headlight aim after changing a bulb?

A correctly seated bulb of the right type shouldn't change the aim, because the beam pattern is set by the headlight unit. But a bulb that isn't sitting flat in its socket can throw the beam off.

If the beam looks noticeably higher, lower or patchier than the other side when you shine it at a wall, check the bulb is seated properly. Headlamp aim is part of the MOT, so if in doubt have a garage or MOT tester check it.

Should I change both headlight bulbs?

Many drivers do. The bulb on the other side has done the same hours and may not last much longer, and a new bulb can look brighter or a slightly different colour from an old one. Our guide on whether to replace headlight bulbs in pairs explains the reasoning.

A failed headlight would fail the MOT, and driving with defective lights can lead to a fixed penalty, so it's worth carrying a spare of the right type.

Check your car

Get the exact bulb codes for every position before you start, checked against the handbook or two independent sources. Start at bulbs by car or choose your make. Popular headlight lookups:

• Vauxhall Corsa E — H7 dipped, H7 main
• Nissan Qashqai J11 — H11 dipped, HB3 main
• VW Golf Mk7 — H7 dipped, H15 main
• Hyundai i10 — H4 dipped and main
• Ford Focus Mk3 — H7 dipped, H1 main

Values can split by facelift or headlight type; the car page shows any split.

Common questions

Do I need tools to change a headlight bulb?

Often not. Many halogen bulbs are reached by hand from under the bonnet. Some cars need a screwdriver or socket to remove an access panel, the air box or the battery cover; the handbook will say.

Why won't the new bulb go in?

It's probably the wrong type, or the tabs on the base aren't lined up with the slots. Compare it with the old bulb. Different headlight bulb types have different bases and won't fit each other's sockets.

My new bulb works but the other side is dimmer. Why?

The old bulb on the other side has aged. Replacing both gives an even output and colour.

Can I change a xenon bulb myself?

It's best not to. Xenon systems use a high-voltage igniter, so leave them to a garage.

Checked against our verification rules. Spotted something wrong? Tell us.