Third Brake Light

This procedure replaces the third brake light (center high-mount stop lamp/CHMSL) assembly on the 2008 Dodge Viper, accessible from the rear exterior of the vehicle.

Warnings

Tools required

Parts

• Third brake light assembly × 1 — Mopar 04805933AA or equivalent
• Third brake light gasket/seal × 1 — Use OEM specification if damaged

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition off and remove key
3. Disconnect negative battery terminal and wait 2 minutes for system capacitors to discharge
4. Clean area around third brake light assembly to prevent debris from entering housing during removal

Procedure

1. 1

   Access third brake light fasteners
   Locate the third brake light (CHMSL) assembly on the rear of the vehicle. Its exact mounting location varies by Viper body style (coupe vs convertible), so visually confirm the assembly before proceeding. Inspect the perimeter for fasteners or retaining clips and determine the access method for your specific vehicle.
2. 2

   Remove third brake light fasteners
   Remove the fasteners securing the third brake light assembly. The exact count and fastener type for the 2008 Viper are unverified — inspect the assembly to confirm before removal, and retain all fasteners for reinstallation.
3. 3

   Separate assembly from body
   Gently pull the third brake light assembly away from the body panel. The assembly may be sealed with a gasket or weatherstrip adhesive. Use a plastic trim tool if needed to carefully separate the assembly from the mounting surface, working around the perimeter gradually to avoid cracking the lens or housing. Do not force—if resistance is excessive, verify all fasteners have been removed.
4. 4

   Disconnect electrical connector
   With the assembly pulled away from the body approximately 2-4 inches, locate the electrical connector on the rear of the lamp housing. Press the release tab on the connector and pull the connector straight off the lamp assembly. Support the assembly with one hand to prevent it from falling or hanging by the wiring harness.
5. 5

   Remove old assembly and inspect gasket
   Remove the third brake light assembly completely from the vehicle. Inspect the mounting surface on the body panel and the gasket/seal. If the gasket is torn, compressed, cracked, or remains stuck to the body panel, carefully peel it off and clean the mounting surface with a shop towel. Check for any moisture intrusion or corrosion in the mounting area.
6. 6

   Prepare new assembly
   If installing a new third brake light assembly, verify the bulbs are properly seated in the new assembly or transfer bulbs from the old assembly if replacement assembly does not include bulbs. If replacing only the bulbs in the original assembly, remove the bulb socket(s) by rotating counterclockwise and replace bulb(s) as needed. Ensure any gasket or seal is properly positioned on the new assembly mounting flange.
7. 7

   Connect electrical connector
   Position the third brake light assembly near its mounting location and reconnect the electrical connector to the lamp assembly. Push firmly until the connector locks with an audible click. Gently tug on the connector to verify it is fully seated and locked.
8. 8

   Test brake light function before final installation
   Defer function testing until after final installation (see Verification section). If a pre-installation check is desired, temporarily reconnect the negative battery terminal only after all hands are clear of moving/electrical components. Have an assistant press the brake pedal while you verify the third brake light illuminates properly. Check for full brightness and that all LED segments or bulb elements light up. If the light does not function, recheck the electrical connector and bulb installation. Once verified, disconnect the negative battery terminal again before proceeding.
9. 9

   Install assembly to body panel
   Align the third brake light assembly with the mounting holes in the rear body panel. Ensure the gasket or seal is properly positioned between the assembly and body to provide weatherproof sealing. Press the assembly firmly into position, seating it evenly around the entire perimeter.
10. 10

    Install and torque fasteners
    Install the 2 Torx fasteners finger-tight first, ensuring the assembly is properly aligned and seated. Then tighten the fasteners in a cross-pattern (if applicable) to seat the assembly evenly and avoid distorting the housing. Tighten securely but do not overtighten, as excessive torque can crack the plastic housing or lens. Tighten only until snug — do not overtighten, as excessive torque can crack the plastic housing. Refer to the factory service manual for a specific torque value if one is provided.

Reassembly

1. Reconnect negative battery terminal and torque to manufacturer specification (typically 15-20 ft-lbs for battery terminals)
2. Verify no tools or fasteners remain on or near the vehicle before testing

Verification

• With ignition on or engine running, press brake pedal and verify third brake light illuminates at full brightness
• Check that all LED segments or bulb elements illuminate evenly without dark spots
• Have an assistant confirm brake light is visible from 50+ feet behind the vehicle in daylight conditions
• Inspect the perimeter of the assembly for proper seating against the body panel with no gaps or misalignment
• Verify the assembly is secure with no rattles or movement when pressed firmly by hand
• Test brake lights at night or in low-light conditions to ensure proper function before operating vehicle on public roads

Related trouble codes on this vehicle

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