1. Faulty Brake Light Switch: The brake light switch, which is usually located near the brake pedal, could be faulty or have poor electrical contact. This switch should send a signal to the brake light bulbs when the brake pedal is depressed.
2. Poor Wiring Connection: There could be loose or corroded electrical connections related to the brake circuit, either in the wiring between the brake light switch and the brake lights, or around the fuse box.
3. Fuse Issues: Check the fuse for the brake lights specifically. A blown fuse can interrupt power supply to the brake lights. Replace the fuse if it's blown.
4. Brake Light Bulbs: Check if the brake light bulbs themselves are burned out. If they are, replace them with new ones.
5. Electrical Short: There might be an electrical short somewhere in the system, preventing the brake lights from functioning correctly.
6. Brake Light Relay: Some vehicles, including older Civic models, may have a separate relay that controls the brake lights. If this relay is faulty, the brake lights may not come on when they should.
7. Faulty Turn Signal Switch: In some cases, the turn signal switch (also called the combination switch) which is located on the steering column, could also affect the brake lights.
If you've checked all of the above and still have issues, it would be best to have your vehicle inspected by a qualified mechanic or automotive electrician to properly diagnose and fix the problem.
