2017-2023 Tesla Model 3 Third Brake Light: Failure, Diagnosis, and Replacement

Symptoms of Failure

The most obvious sign of a problem with your Model 3's third brake light is a warning message on the touchscreen. You can also have someone stand behind the car while you press the brake pedal to visually check its operation. Symptoms are typically straightforward:

• Complete Failure: The entire light strip does not illuminate when the brake pedal is pressed. This is the most common failure mode.
• Partial Failure or Flickering: Only a section of the LED strip lights up, or the light flickers intermittently. This points to a developing internal fault within the sealed unit.

Known Issues & Recalls

Water Stains from Window Tinting

A common cosmetic issue reported by owners is the appearance of water stains or a hazy film on the inside of the third brake light lens. This is almost always caused by the application of aftermarket window tint on the rear glass. The liquids used in the tinting process can run down and get trapped between the light assembly and the glass, leaving residue as they dry. While this doesn't typically cause electrical failure, it is unsightly. Some tint shops can clean this, but it may require partial removal of the light assembly.

Light Bleed into the Cabin

Some owners have noted that they can see the red glow of the third brake light from inside the car, reflected in the rear window at night. 🎬 Watch: How to fix light bleed from your brake light. This is often due to a poor seal or improper fit of the light assembly against the package shelf, allowing light to escape upwards. It can be distracting and usually indicates the light was not seated correctly during a previous repair.

Related Recalls (Firmware)

In November 2022, Tesla issued a recall (NHTSA Campaign: 22V835) for a firmware anomaly that could cause the main taillights (not the brake lights) to fail to illuminate on some 2023 Model 3 and 2020-2023 Model Y vehicles. The recall documents specifically state that the brake lights, including the center high-mount light, were not affected by this condition but it is a point of common confusion. This issue was resolved with an over-the-air (OTA) software update.

Buying a Used Center High Mount Stop Light

Since this is a sealed LED unit, a high-quality, tested used OEM part is an excellent alternative to an expensive new one. Aftermarket options are not common for this specific part. Here’s what to look for when buying a recycled assembly:

• Inspect the Lens: Check the red plastic lens for any cracks, deep scratches, or signs of hazing. Cracks can allow moisture to enter, which will destroy the internal electronics.
• Check for Water Damage: Look for any signs of dried water spots, mineral deposits, or a foggy film on the *inside* of the lens. This indicates the seal has failed and the part should be avoided.
• Examine the Housing and Connectors: Ensure the black plastic housing is not cracked and that all mounting tabs and screw holes are intact. The electrical connector pins should be clean, straight, and free of any corrosion.
• Verify the Part Number: The OEM part number is typically printed on the unit. The base number is 1077405. It is followed by a revision suffix like -00-F, -00-G, -00-H, or -00-I. While any of these should fit, it's always best to get the latest revision possible (e.g., '-I') as it may include small improvements.

Replacement Procedure Overview

Replacing the third brake light on a Model 3 is a feasible DIY project for someone comfortable with interior trim removal, but it is more involved than on many other cars. The official Tesla service procedure outlines accessing it from inside the vehicle.

1. Remove Rear Seat Bolsters: The side bolsters for the rear seats must be removed to access the C-pillar trim.
2. Remove C-Pillar and Side Rail Trims: The upper C-pillar trim panels and side rail trims on both the left and right sides must be taken off.
3. Remove Package Tray: With the side trims out, the rear package tray (the shelf behind the rear seats) can be removed.
4. Disconnect and Remove the Light: Disconnect the electrical connector from the light assembly. Remove the two screws holding it to the package tray. Release the clips securing the light and remove it from the vehicle.
5. Installation: Installation is the reverse of removal. Install the new light, ensuring it clips in securely. Tighten the mounting screws to the specified torque of 0.5 Nm (4 lbs-in). Reconnect the electrical connector and test the light before reassembling all the interior trim panels.

Cost Comparison

The cost to replace a Model 3 third brake light can vary significantly depending on the source of the part and who performs the labor.

Frequently Asked Questions (FAQ)