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Headlight Not Working

A headlight that does not light usually has a blown bulb, but a failed fuse, a corroded connector, a faulty relay or, on LED and xenon lights, a failed control module or ballast are also common.

High risk

Fix it soon. Driving with a headlight out reduces visibility and is not legal in many countries.

Short answer · Why is one of my headlights not working?

Bulbs burn out with age and vibration. If both sides fail at once, check fuses and relays or the light switch. Corroded connectors stop current. Xenon lights use a ballast that can fail, and LED headlights often have internal drivers. A bulb out warning on the dashboard helps confirm which light is affected.

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Safe checks you can do

  1. Check which beams workDipped, main beam and sidelights on each side.
  2. Swap the bulb if possibleA new bulb is the simplest test on halogen lights.Xenon systems use high voltage; leave them to a workshop.
  3. Check the fusesUse the fuse chart in the owner's manual.

Questions that narrow it down

  1. Are both sides out?Fuse, relay or switch.
  2. Is it xenon or LED?Ballast or module faults are common.
  3. Is there a bulb warning?Confirms the circuit.

Possible causes

Listed without ranking. Use the questions above to see which ones fit your car.

  1. Blown bulbMost common on halogen lights.
  2. Blown fuseOne or both lights out.
  3. Corroded connectorIntermittent or no light.
  4. Failed relayBeam does not switch on.
  5. Ballast or LED module faultXenon or LED lights.

Questions about Headlight Not Working

Should bulbs be changed in pairs?

Many people do so the brightness matches.

Will a new bulb need aiming?

Usually not, but a beam check after work is sensible.