Bulb Replacement
Headlights, sidelights, indicators, brake lights and number-plate bulbs all blow eventually. Most are 5-10 minute swaps once you can access the bulb housing. A blown bulb is also a quick MOT failure — keep spares.
Covers the universal process and the don't-touch-with-bare-fingers rule. Same approach for most bulbs.
NEVER touch a halogen bulb's glass with bare fingers. Skin oil creates a hot spot that burns out the bulb in days. Use a tissue or gloves.
Always replace bulbs in PAIRS (both front headlights, both brake lights). The other one is usually about to go too, and matched bulbs give even output.
Buy quality brands — Osram Night Breaker, Philips X-treme Vision. Cheap bulbs dim and fail fast.
On many modern cars the headlight bulb is accessed through the wheel arch liner or by removing a battery / airbox. Allow extra time the first time.
Identify which bulb has blown — walk around the car with someone pressing the relevant switch
Look up the bulb type in the handbook (e.g. H7, H4, P21W, W5W)
Buy a matching bulb. Pick up two if doing both sides — always replace in pairs
Open the bonnet (or boot, depending on which bulb)
Find the back of the bulb housing. Remove dust covers, clips or twist-connectors as needed
Disconnect the wiring plug from the bulb
Release the bulb retaining clip or twist the bulb anti-clockwise
Pull the bulb straight out. Note the orientation
Insert the new bulb WITHOUT touching the glass. Use a tissue or wear gloves
Refit the retaining clip or twist clockwise to lock
Reconnect the wiring plug
Refit dust cover. Test the bulb works before closing up
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