how to troubleshoot the fog lights not working in my Toyota Highlander Third Generation (2014-2019)?

Toyota Highlander Third Generation (2014-2019)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

593 words

Problem Statement

Learn how to troubleshoot and fix fog lights not working on your 2014-2019 Toyota Highlander. Step-by-step guide with diagnostic and repair instructions.

Affected Component

Electrical

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the vehicle to cool before working on any components near the engine or exhaust.

Symptoms

•Fog lights do not illuminate when switched on
•Dashboard warning light for fog lights may be illuminated or absent
•No unusual sounds or flickering when the fog light switch is activated
•Working headlights but non-functional fog lights
•Possible blown fuse related to fog light circuit

Diagnostic Steps

1
Inspect the fog light bulbs visually for any signs of damage or burnout.
2
Check the fog light fuse in the fuse box for continuity or any visible damage.
3
Use an OBD-II scanner to check for any related error codes that might indicate electrical issues.
4
Test the fog light switch for proper operation using a multimeter.
5
Inspect the wiring harness and connections for any signs of wear, corrosion, or loose connections.
6
Verify that the fog light relay is functioning properly.

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

•Screwdriver set
•Multimeter
•Fuse puller
•Pliers

Parts Required

•Fog light bulbs (if burned out)
•Fuse (if blown)
•Fog light relay (if faulty)

Related Faults

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Diagnostic Steps

1
Inspect the fog light bulbs visually for any signs of damage or burnout.
2
Check the fog light fuse in the fuse box for continuity or any visible damage.
3
Use an OBD-II scanner to check for any related error codes that might indicate electrical issues.
4
Test the fog light switch for proper operation using a multimeter.
5
Inspect the wiring harness and connections for any signs of wear, corrosion, or loose connections.
6
Verify that the fog light relay is functioning properly.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Bulbs

Remove the fog light assembly from the vehicle:
1. Locate the fog light assembly under the front bumper.
2. Unscrew any retaining screws or clips to detach the assembly.
Remove the bulb from the assembly:
1. Twist the bulb socket counterclockwise to remove it.
2. Replace the bulb with a new one of the same type (check the owner’s manual for specifications).
Reinstall the bulb and fog light assembly in reverse order.

3. Check and Replace Fuse

Locate the fuse box:
1. Refer to the owner's manual for the exact location of the fog light fuse.
Remove the fog light fuse:
1. Use a fuse puller or pliers to carefully extract the fuse.
Inspect the fuse for continuity:
1. If blown, replace it with a fuse of the same amperage (usually 10A or 15A for fog lights).

4. Test the Fog Light Switch

Reconnect the battery.
Use a multimeter to test the fog light switch:
1. Set the multimeter to the ohm setting.
2. Check for continuity when the switch is activated; replace if necessary.

5. Inspect Wiring and Relay

Check the wiring harness:
1. Look for damaged wires, corrosion, or loose connections.
2. Repair or replace any damaged wiring.
Test the fog light relay:
1. Locate the relay in the fuse box and swap it with a similar relay.
2. If the fog lights work with the swapped relay, replace the faulty relay.