Fits: 2015-2023 Ford Mustang S550.
Required Tools
- Ratchet
- 10mm deep socket
- Trim panel removal tool (or flathead screwdriver)
Part 1: Remove the Factory Tail Lights
Step 1: Remove the Trunk Trim Panel
Open the trunk and find the large plastic knobs securing the rear trim panel. Unscrew them by hand and pull the trim panel straight up to remove it.
Step 2: Remove the Side Liner Pins
Use a trim removal tool to pop out the plastic push pin securing the side trunk liner. Peel back the liner to reach the tail light mounting nuts.
Step 3: Disconnect the Factory Plug
Find the factory wiring harness connector. Press the release tab and disconnect the plug from the tail light housing.
Step 4: Unscrew the Mounting Nuts
Use a 10mm socket to remove the three nuts securing the tail light to the body. Keep the nuts; you will reuse them.
Step 5: Remove the Tail Light Assembly
From the outside, firmly pull the tail light straight back to release it from the body clips. Remove the rubber grommet together with the harness.
Part 2: Install the New Tail Lights
Step 6: Feed the Harness Through the Body
Feed the wiring harness of the new tail light through the hole in the body. Press the rubber grommet firmly into place for a watertight seal.
Step 7: Secure the New Light
Line up the new tail light and push it in until it clicks. From inside the trunk, reinstall the three factory 10mm nuts and tighten them securely.
Step 8: Connect and Test
Connect the new tail light plug to the factory harness until it clicks. Test the brake, turn signals, and reverse lights before reinstalling the trunk liner.
The standard version is now fully installed. The next section applies only to RGB models.
Part 3: RGB Models: Happy Lighting App Setup
Scan the QR code on the box to download the control app, then connect over Bluetooth to change colors and modes.
- The Happy Lighting app controls the colors and animation modes of the light bar. The startup animation is preset and cannot be changed.
- Download: search for "Happy Lighting" in the App Store or Google Play, or scan the QR code on the controller box.
- Pairing: turn on Bluetooth on your phone. Open the app, tap the menu icon (arrow 1), and select your device from the list (arrow 2).
- Color: tap the Adjust tab (arrow 3) and use the color wheel (arrows 4 and 5) to choose a solid color.
- Dynamic modes: tap the Music or Mode tab (arrow 6) to choose an animation. Use slider 8 to adjust speed and slider 9 to adjust brightness.
Common Issues and Solutions
Tail light does not turn on after installation. Check that the harness connectors are fully seated. Inspect the pins inside each connector; if any are bent, carefully straighten them with a small precision tool and reconnect securely.
Swap test. If a tail light still does not work, swap the left and right units to find out whether the issue is the light itself or the vehicle wiring.
Condensation inside the tail light. Temperature differences can cause light condensation, which is normal. Once the light has been on for a while and the internal temperature stabilizes, the moisture clears on its own. It does not affect brightness, performance, or lifespan.
