Symptoms
- Headlight flickers intermittently while driving
- Flickering worsens over bumps or rough roads
- Other lights may flicker at the same time
- Headlight eventually goes out completely after a period of flickering
Likely causes
- CommonLoose or corroded bulb connectorA poor connection can cause intermittent contact, especially over bumps.
- CommonFailing bulb nearing end of lifeBulbs often flicker briefly before burning out completely.
- PossibleCharging system issue (weak alternator or battery)If multiple lights flicker together, especially at idle, suspect the charging system.
- PossibleDamaged wiring near the headlightWear from vibration or a previous repair can cause an intermittent connection.
What to do
- Note if only one headlight flickers or if other lights flicker too, which helps distinguish a local issue from a charging system issue.
- Check the bulb connector for looseness or corrosion and reseat it firmly.
- If other electronics also flicker, especially at idle, have the battery and alternator tested.
- Replace the bulb if flickering continues after confirming the connector is solid, since this is often a sign of a dying bulb.
- Inspect visible wiring near the headlight for any fraying or damage.
- Avoid ignoring flickering, since it often precedes a complete bulb failure.
- Have a shop trace wiring if a new bulb and clean connector don't stop the flickering.
- Get the charging system checked as a priority if flickering affects multiple lights across the car.
Tools and parts
- Flashlight
- Multimeter (optional)
Headlight bulbSearch: “headlight bulb for [your car make model year]”
When to call a pro
If flickering is paired with other electrical symptoms, have the charging system tested before assuming it's just the bulb.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.