Lights

Daytime running lights aren't turning on

Daytime running lights (DRLs) that stay off usually indicate a blown fuse, a bad relay, or a module fault, since they're a separate circuit from regular headlights on many vehicles.

Difficulty
Moderate
Time
20–45 minutes
DIY cost
$10–$40
Pro cost
$60–$250

Symptoms

  • No lights come on automatically when the car starts during the day
  • Regular headlights and taillights work fine when manually turned on
  • DRL indicator or warning light may appear on the dash
  • Lights work fine at night when headlights are used

Likely causes

  • CommonBlown DRL fuseDaytime running lights often run through their own dedicated fuse separate from headlights.
  • CommonFailed DRL relay or moduleA relay or dedicated module controls DRL activation and can fail independently of the headlights.
  • PossibleBurned out DRL bulb (on vehicles with separate DRL bulbs)Some vehicles use a separate small bulb just for daytime running lights.
  • Less commonAmbient light sensor issueSome systems use a light sensor to decide when DRLs are needed, which can malfunction.

What to do

  1. Confirm that regular headlights work fine when manually switched on, which narrows the issue to the DRL-specific system.
  2. Check the fuse box for a blown DRL fuse and replace with the correct amperage.
  3. Locate and test the DRL relay if your vehicle uses one, swapping with an identical relay to test.
  4. Check if your vehicle uses separate DRL bulbs and inspect them for burnout if applicable.
  5. Look for any DRL-specific warning light or message on the dashboard.
  6. Check the ambient light sensor location (often near the top of the dash) for obstruction if your vehicle uses one.
  7. Have a shop scan for any stored codes related to the DRL module if basic checks don't reveal the cause.
  8. Note that in most areas, non-working DRLs aren't a safety issue as long as regular headlights work, but should still be fixed.

Tools and parts

  • Fuse puller or pliers
  • Replacement fuses
DRL relay or bulbSearch: “daytime running light relay for [your car make model year]”

When to call a pro

If your regular headlights work fine, a non-working DRL system isn't an emergency, but a shop can quickly diagnose the module or relay involved.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.