This procedure addresses the fact that the 1966 Chevrolet Corvette was not originally equipped with a third brake light (center high-mounted stop lamp), as this component was not federally mandated until 1986.

Warnings

Preparation

1. Verify local and state regulations regarding third brake light installation on classic vehicles - many jurisdictions exempt pre-1986 vehicles from this requirement
2. If proceeding with installation, determine mounting location (common options: rear deck lid on coupe, rear parcel shelf visible through back glass, or aftermarket spoiler with integrated lighting)
3. Select an appropriate LED third brake light assembly designed for retrofit applications
4. Disconnect negative battery cable and wait 5 minutes before working on electrical systems
5. Gather wiring materials: 16-gauge automotive wire, crimp connectors, electrical tape, and wire routing clips
6. Review factory wiring diagram for brake light circuit to identify tap-in point at existing brake light switch or rear lamp harness

Procedure

1. 1

   Evaluate Installation Necessity and Legality
   Confirm whether your intended use of the vehicle (show, occasional drive, daily driver) and local regulations require or benefit from a third brake light installation. The 1966 Corvette is exempt from FMVSS 108 requirements as a pre-1986 vehicle. If the vehicle is primarily a collector car or show vehicle, consider that any body modification will negatively impact originality and value. If installation is not legally required or practically necessary, professionally recommend maintaining the vehicle in original configuration.
2. 2

   Determine Mounting Location and Method
   For coupe models, identify mounting location on the interior parcel/rear deck shelf visible through the rear glass (note: the 1966 coupe has no external trunk/deck lid). For convertible models, consider interior mounting behind the seats or on an aftermarket luggage rack. For convertible models, consider interior mounting behind seats or on aftermarket luggage rack. Avoid drilling through the original fiberglass body if possible. Use adhesive mounting or existing fastener locations. Measure and mark the mounting position ensuring it is centered on the vehicle centerline and will not obstruct rearward visibility.
3. 3

   Route Power Wire from Brake Light Circuit
   Access the existing brake light wiring at the rear of the vehicle. The brake light circuit can be tapped at either rear taillight assembly. Remove the lens assembly by removing the screws securing each lens (verify exact screw count against a service manual for the 1966 Corvette). Identify the brake (stop) lamp feed wire by using a test light with the brake pedal depressed; do not rely on wire color alone, as factory color coding varies — confirm the live feed with the test light before tapping. Prepare a 16-gauge wire of sufficient length to route from the tap point to the third brake light location. Use a crimp-type tap connector or solder and heat-shrink connection to tap into the existing brake light power wire.
4. 4

   Route and Secure Wiring
   Route the power wire from the tap point to the third brake light mounting location, following existing wire harness paths where possible. On coupes, route along the interior rear storage/parcel shelf area, accessed from inside the cabin (the coupe has no external trunk). On convertibles, route along the interior side panels. Secure wiring with plastic wire clips every 12 inches, keeping wire away from sharp edges, moving parts, and heat sources. Ensure adequate slack for body flexing and for movement of any trim panels or luggage rack the wiring passes near.
5. 5

   Install Third Brake Light Assembly
   Mount the third brake light assembly at the predetermined location using the manufacturer's supplied hardware or adhesive backing. If drilling is absolutely necessary, use a pilot hole and ensure you are not penetrating into structural areas or creating water intrusion points. Connect the power wire to the positive terminal of the brake light assembly. Connect a separate 16-gauge ground wire from the brake light ground terminal to a nearby chassis ground point, ensuring clean metal-to-metal contact by removing paint if necessary.
6. 6

   Test Brake Light Function
   Reconnect the negative battery cable. Turn the ignition to the ON position and have an assistant depress the brake pedal while you observe all three brake lights (left, right, and new center light). Verify that all lights illuminate simultaneously and with equal brightness. Verify that brake lights extinguish completely when pedal is released. Check for any flickering or dimming that would indicate poor connections or inadequate wire gauge.

Reassembly

1. Reinstall any interior trim panels or trunk components that were removed for wire routing access
2. Secure all loose wiring with additional clips to prevent rattling or chafing
3. On coupe models, verify rear deck lid operation is not impeded by wiring or light assembly
4. Clean any fingerprints or adhesive residue from the third brake light lens

Verification

• With vehicle in a safe location, have an assistant observe all brake lights while you depress the brake pedal from the driver's seat - all three brake lights should illuminate brightly and simultaneously
• Verify third brake light is visible from 100 feet behind the vehicle in daylight conditions
• Check that no existing brake light function has been compromised by the tap connection
• Inspect all electrical connections for proper insulation and strain relief
• Test brake lights with engine running and all electrical accessories on to ensure adequate charging system capacity

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