Both headlights are out at the same time

Symptoms

• No headlights at all, high or low beam
• Other exterior lights (taillights, turn signals) still work
• Dashboard lights and other electronics work normally
• Headlights worked fine until suddenly going out together

Likely causes

• CommonBlown headlight fuseMany vehicles run both headlights through a single shared fuse.
• CommonFailed headlight relayA relay that controls power to both headlights can fail and take both out at once.
• PossibleFaulty headlight switchThe dash switch used to turn on headlights can fail internally.
• PossibleDaytime running light module faultSome vehicles use a module to control headlights that can develop a fault.

What to do

1. Check the fuse box for a blown headlight fuse and replace with the correct amperage.
2. Locate the headlight relay (often in the engine bay fuse/relay box) and try swapping with an identical relay to test.
3. Try the headlight switch in different positions (parking lights, low beam, high beam) to see if any position works.
4. Check if daytime running lights or fog lights still work, which can help narrow down which part of the system failed.
5. Listen for a click from the relay location when turning the switch on and off.
6. Avoid driving at night with no headlights; wait until at least one basic lighting option works or get a tow.
7. Have a shop test the switch and wiring if fuses and relays check out fine.
8. Get the daytime running light module inspected if your vehicle uses one and other checks come up empty.

Tools and parts

• Fuse puller or pliers
• Replacement fuses
• Flashlight

When to call a pro

If both headlights fail suddenly and fuses/relays are fine, a shop can trace the switch or module wiring efficiently with the right diagrams.

Safety