my Ford F-150 Fourteenth Generation (2021-present) rear lights are not working, what should I check

Ford F-150 14th Generation (2021-2024)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

4 min read

612 words

Problem Statement

Learn how to diagnose and fix rear lights not working on your 2021 Ford F-150. Step-by-step guide with symptoms, diagnostic steps, 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 to prevent shock or short circuits

Symptoms

•Rear lights do not illuminate when headlights are activated
•Brake lights are non-functional
•Turn signals at the rear do not work
•Check engine light may be illuminated (related to electrical issues)
•Warning message on dashboard related to exterior lights

Diagnostic Steps

1
Verify that the headlight switch is in the correct position (not in the OFF position)
2
Inspect the rear light bulbs for any signs of burn-out or damage
3
Check the fuse for the rear lights in the fuse box (refer to the owner's manual for location)
4
Use an OBD-II scanner to check for any related fault codes
5
Test the wiring harness and connectors for corrosion or loose connections
6
Check the brake light switch 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
•OBD-II scanner
•Flathead screwdriver
•Fuse puller

Parts Required

•Rear light bulbs (if needed)
•Replacement fuses (if needed)

Related Faults

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Diagnostic Steps

1
Verify that the headlight switch is in the correct position (not in the OFF position)
2
Inspect the rear light bulbs for any signs of burn-out or damage
3
Check the fuse for the rear lights in the fuse box (refer to the owner's manual for location)
4
Use an OBD-II scanner to check for any related fault codes
5
Test the wiring harness and connectors for corrosion or loose connections
6
Check the brake light switch for proper operation

Solution

1. Preparation

Tools Required: Multimeter, socket set, OBD-II scanner, flathead screwdriver, fuse puller.
Disconnect the vehicle battery negative terminal to ensure safety before proceeding with electrical work.

2. Inspect and Replace Bulbs

Open the rear tailgate and access the rear light assembly.
Remove the screws or clips securing the tail light assembly using the socket set or flathead screwdriver.
Gently pull the tail light assembly away from the vehicle.
Twist and remove the bulb sockets from the assembly.
Inspect the bulbs for any filament breakage or discoloration; replace with new bulbs if defective. Ensure the new bulbs match the specifications in the owner's manual.
Reassemble the tail light assembly by reversing the removal steps.

3. Check and Replace Fuses

Locate the fuse box, which is usually found under the dashboard or in the engine compartment (consult the owner’s manual for exact location).
Identify the fuse associated with the rear lights (refer to the fuse diagram on the cover).
Use a fuse puller to remove the fuse and inspect it for continuity.
If the fuse is blown, replace it with one of the same rating (typically 15A for rear lights).
Reinstall the fuse and close the fuse box.

4. Test Wiring and Connections

Reconnect the vehicle battery negative terminal.
Use a multimeter to check for voltage at the rear light connector while the headlights are on.
If no voltage is present, inspect the wiring harness for damage or corrosion.
Repair or replace any damaged wiring or connectors as needed.

5. Verify Brake Light Switch Function

Locate the brake light switch, usually mounted near the brake pedal.
Check for proper operation by pressing the brake pedal and observing if the switch activates.
Replace the switch if it does not function correctly.