how to fix the fog lights that won't turn on in my Toyota Highlander

Toyota Highlander Third Generation (2014-2019)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

530 words

Problem Statement

Learn how to diagnose and fix fog lights that won't turn on in your Toyota Highlander. Step-by-step guide with tools and parts required.

Affected Component

Electrical

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems to avoid short circuits or electrical shock.

Symptoms

•Fog lights do not illuminate when switched on
•Dashboard indicator for fog lights is not illuminated
•No sound from relay clicking when fog lights are activated
•Other lights (headlights, turn signals) function normally
•Possible blown fuse for fog lights

Diagnostic Steps

1
Inspect the fog light bulbs for burnt-out filaments or damage.
2
Check the fog light fuse in the fuse box for continuity.
3
Test the fog light switch operation using a multimeter.
4
Verify voltage at the fog light connectors with a multimeter.
5
Inspect the wiring harness for any visible damage or corrosion.
6
Test the fog light relay for proper operation.

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
•Socket set
•Fuse puller
•Screwdriver set

Parts Required

•Fog light bulbs (specific to model)
•Fog light fuse (if blown)
•Fog light relay (if faulty)

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Diagnostic Steps

1
Inspect the fog light bulbs for burnt-out filaments or damage.
2
Check the fog light fuse in the fuse box for continuity.
3
Test the fog light switch operation using a multimeter.
4
Verify voltage at the fog light connectors with a multimeter.
5
Inspect the wiring harness for any visible damage or corrosion.
6
Test the fog light relay for proper operation.

Solution

1. Preparation

Gather tools: multimeter, socket set, fuse puller, and replacement bulbs.
Disconnect the vehicle battery to ensure safety while working on electrical components.

2. Inspect and Replace Fog Light Bulbs

Locate the fog light assemblies under the front bumper.
Remove the fog light housing by unscrewing the retaining screws.
Disconnect the wiring harness from the fog light.
Remove the old bulb by twisting it counterclockwise and replace it with a new bulb.
Reconnect the wiring harness and reassemble the fog light housing.

3. Check and Replace the Fog Light Fuse

Locate the fuse box; refer to the owner's manual for the exact location.
Use a fuse puller to remove the fog light fuse (check the fuse rating in the manual).
Inspect the fuse for continuity; replace it with a new fuse of the same rating if blown.
Reinstall the fuse and close the fuse box.

4. Test the Fog Light Relay

Locate the fog light relay in the fuse box; use the owner's manual for the exact location.
Remove the relay and test it using a multimeter to check for continuity.
If the relay is faulty, replace it with a new relay of the same specifications.

5. Final Assembly and Testing

Reconnect the battery.
Turn the fog lights on to test if they are functioning properly.
Ensure all components are securely fastened and recheck for any loose connections.