Safety First:
* Disconnect the battery's negative terminal before starting any work to prevent electrical shocks.
* Work in a well-lit area.
* Use appropriate tools. You'll likely need a screwdriver (possibly Phillips and/or flathead), possibly pliers, and potentially a socket wrench depending on the bulb type and retainer.
Steps (General):
1. Identify the faulty brake light(s). Have someone help you by stepping on the brake pedal while you visually inspect the taillights.
2. Access the taillight assembly. This usually involves removing trim pieces around the taillights. On a '66 Fleetwood, this might involve removing interior panels, exterior trim pieces, or even the entire taillight housing. Pay close attention to how things come apart; take pictures as you go if necessary. Some screws might be hidden under chrome or plastic trim pieces.
3. Disconnect the electrical connector. This connector usually has a clip or latch that needs to be released to separate it from the taillight assembly. Be gentle to avoid damaging the connector.
4. Remove the taillight assembly. Once the connector is disconnected, the assembly might simply pull out, or there might be additional retaining clips or screws holding it in place.
5. Access the brake light bulb(s). Inside the taillight housing, you'll find the bulb socket(s). There might be a spring clip or a twist-lock retainer holding the bulb in place. Carefully remove the bulb(s).
6. Replace the bulb(s). Make sure you get the correct bulb type. Your owner's manual or a parts store should be able to tell you the correct wattage and type (e.g., 1157, 1141, etc.). Insert the new bulb(s) firmly into the socket.
7. Reassemble everything. Carefully reverse the steps you took to disassemble the taillight assembly. Make sure all the connectors are secure and that the taillight assembly is properly seated.
8. Reconnect the battery.
9. Test the brake lights. Have someone press the brake pedal while you check to see if the new bulbs are working correctly.
Important Considerations for a 1966 Cadillac Fleetwood:
* Age and fragility: Parts on a 50+ year-old car can be brittle and prone to breaking. Work slowly and carefully.
* Rust: Rust can make removing screws and other fasteners difficult. Penetrating oil might help.
* Bulb types: The exact bulb type for your car's brake lights might be uncommon now. A parts store specializing in classic cars or an online retailer specializing in classic car parts would be your best bet for replacements.
* Wiring: Inspect the wiring for any damage or corrosion while you have the taillight assembly out. Repair or replace any damaged wiring as needed.
If you're uncomfortable working on your car yourself, it's best to take it to a mechanic, especially one who specializes in classic cars. They'll have the experience and the right tools to do the job correctly. Attempting this without experience could lead to further damage to your vehicle.
