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How can I troubleshoot the non-functioning headlights in my 2021 Toyota Highlander? - Toyota Highlander
Home/Cars/Toyota/Highlander/Fourth Generation (2020-present)/How can I troubleshoot the non-functioning headlights in my 2021 Toyota Highlander?

How can I troubleshoot the non-functioning headlights in my 2021 Toyota Highlander?

Toyota Highlander Fourth Generation (2020-present)

Error Codes
1-2 hours
Time
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
4 min read
674 words

Problem Statement

Learn how to troubleshoot and fix non-functioning headlights in your 2021 Toyota Highlander with this comprehensive guide.

Affected Component
headlights
Estimated Time
1-2 hours

Symptoms

  • •Headlights do not illuminate when switched on.
  • •Dashboard indicator light for headlights may or may not be illuminated.
  • •Fog lights and high beams may still function (if applicable).

Diagnostic Steps

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Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •Multimeter
  • •Screwdriver set (Phillips and flathead)
  • •Wire strippers and crimpers
  • •Electrical contact cleaner
  • •Replacement fuses (if needed)
  • •Safety gloves and goggles
  • •OBD-II Scanner (optional for checking error codes)

Additional Information

Affected Component
headlights
Estimated Time
1-2 hours
Difficulty
medium
Severity
medium
Tools Required
7 items

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Back to Generation
Troubleshooting Non-Functioning Headlights in a 2021 Toyota Highlander
Tools Required
  • Multimeter
  • Screwdriver set (Phillips and flathead)
  • Wire strippers and crimpers
  • Electrical contact cleaner
  • Replacement fuses (if needed)
  • Safety gloves and goggles
  • OBD-II Scanner (optional for checking error codes)

Step 1: Initial Inspection

  1. Check Headlight Switch: Ensure the headlight switch is functioning correctly. Turn the switch between different positions (off, parking lights, low beams, high beams) and check for any change in illumination.
  2. Inspect for Damage: Visually inspect the headlight assembly and wiring for signs of physical damage, corrosion, or loose connections.

Step 2: Check Fuses

  1. Locate Fuse Box: Find the fuse box for the headlights, typically located under the dashboard or in the engine compartment.
  2. Inspect Headlight Fuses: Refer to the owner's manual for the exact fuse locations and specifications. Remove the headlight fuses using a fuse puller or pliers.
  3. Test Fuses: Use a multimeter set to continuity mode to test the fuses. A good fuse will show continuity, while a blown fuse will not.
    • If the fuse is blown, replace it with a new fuse of the same amperage.

Step 3: Check Power Supply

  1. Test Voltage at Headlight Connector: Disconnect the headlight connector. Use a multimeter to check for voltage at the connector while the headlights are turned on.
    • You should see approximately 12V if the system is functioning correctly.
    • If there is no voltage, proceed to check the wiring and relays.

Step 4: Inspect Wiring and Relays

  1. Check Wiring: Inspect the wiring leading to the headlights for any cuts, frays, or corrosion. Pay special attention to any connectors; they should be clean and secure.
  2. Test the Relay: Locate the headlight relay in the fuse box. Remove the relay and test it by swapping it with another relay of the same type (if available).
    • If the headlights work with the swapped relay, replace the faulty relay.

Step 5: Check the Headlight Bulbs

  1. Inspect Bulbs: Remove the headlight bulbs from the assembly. Inspect for any signs of damage or burnt filaments.
  2. Test Bulbs: If you have a multimeter, check for continuity across the bulb terminals. Replace any bulbs that are found to be faulty.
Repair Instructions

Step 1: Replacing Fuses

  1. Remove the blown fuse using a fuse puller or pliers.
  2. Insert a new fuse of the same amperage into the fuse holder.
  3. Reassemble the fuse box cover and test the headlights.

Step 2: Replacing the Relay

  1. Remove the faulty relay from the fuse box.
  2. Insert the new relay into the same socket.
  3. Test the headlights for functionality.

Step 3: Replacing Headlight Bulbs

  1. Disconnect the power connector from the bulb.
  2. Remove the retaining clip or twist the bulb holder (depending on the design) to free the bulb.
  3. Insert the new bulb without touching the glass to avoid contamination.
  4. Reattach the retaining clip or twist the bulb holder back in place.
  5. Reconnect the power connector and test the headlights.
Final Steps
  1. Test Headlight Operation: After replacing any faulty components, turn on the headlights to ensure they are functioning correctly.
  2. Recheck All Connections: Ensure all connectors are secure, and that there are no loose wires in the assembly.
Optional: OBD-II Scan
  • If headlights still do not function after these steps, consider using an OBD-II scanner to check for any related trouble codes that might indicate issues with the vehicle’s electronic control unit (ECU).

By following these detailed steps, you will be able to troubleshoot and resolve the non-functioning headlights in your 2021 Toyota Highlander effectively. If issues persist after these checks, it may be advisable to consult a professional mechanic for further diagnosis.