how to diagnose interior lights staying on in my Ford F-150 13th Generation (2015-2020)

Ford F-150 13th Generation (2015-2020)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

496 words

Problem Statement

Learn how to diagnose and fix interior lights staying on in Ford F-150 (2015-2020). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Electrical

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems to prevent shocks or shorts.

Symptoms

•Interior lights do not turn off after closing the doors.
•Door ajar warning light illuminated on the dashboard.
•Lights remain on when the vehicle is turned off.
•Increased battery drain leading to difficulty starting the vehicle.
•Possible flickering of lights when the vehicle is in motion.

Diagnostic Steps

1
Inspect all door switches for proper operation and damage.
2
Use an OBD-II scanner to check for related fault codes.
3
Manually open and close each door to determine if the lights respond correctly.
4
Inspect the wiring harness for any signs of wear, damage, or corrosion.
5
Test the interior light switch and verify its functionality.
6
Check the Body Control Module (BCM) settings and programming.

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

•OBD-II scanner
•Multimeter
•Torx screwdriver
•Wire stripper/crimper
•Electrical tape

Parts Required

•Replacement door switches (if applicable)
•Interior light switch (if applicable)
•Wiring connectors (if damage is found)

Related Faults

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Diagnostic Steps

1
Inspect all door switches for proper operation and damage.
2
Use an OBD-II scanner to check for related fault codes.
3
Manually open and close each door to determine if the lights respond correctly.
4
Inspect the wiring harness for any signs of wear, damage, or corrosion.
5
Test the interior light switch and verify its functionality.
6
Check the Body Control Module (BCM) settings and programming.

Solution

1. Preparation

Gather tools and parts required for repairs.
Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect Door Switches

Tools Required: Multimeter, Torx screwdriver.
Remove door panels where necessary to access door switches.
Sub-steps:
1. Disconnect the electrical connector from each door switch.
2. Test the switch using a multimeter to ensure it opens and closes correctly.
3. Replace any faulty switches with new components.

3. Check Wiring Harness

Tools Required: Wire stripper/crimper, electrical tape.
Inspect the wiring harness around the door for frays or breaks.
Sub-steps:
1. If damaged wiring is found, repair it using wire splices and electrical tape.
2. Ensure all connections are secure and free from corrosion.

4. Test the Interior Light Switch

Tools Required: Multimeter.
Locate the interior light switch, typically on the overhead console.
Sub-steps:
1. Disconnect the switch and test it with a multimeter to ensure it operates correctly.
2. Replace the switch if it is malfunctioning.

5. Reconnect Battery and Test

Reconnect the negative battery terminal.
Test the functionality of the interior lights by closing the doors and observing if they turn off.