The high mount brake light, also known as the third brake light, is an essential safety feature in vehicles. If this light is not functioning, it can lead to safety concerns and potential traffic violations. This guide will help you troubleshoot and resolve issues related to a non-working high mount brake light.

Common Causes of High Mount Brake Light Failure

Understanding the reasons behind a malfunctioning high mount brake light can simplify the troubleshooting process. Here are some common causes:

  • Burnt Out Bulb: The most frequent issue is a burnt-out bulb. Even if you have replaced it, ensure it matches the specifications required for your vehicle.

  • Faulty Socket or Connector: Corrosion or damage to the socket or connectors can prevent proper electrical contact, leading to failure.

  • Blown Fuse: A blown fuse can interrupt the power supply to the brake light. Check your vehicle's fuse box for any blown fuses related to the brake lights.

  • Brake Light Switch Issues: The brake light switch, located near the brake pedal, may be malfunctioning. If this switch fails, it won't send a signal to activate the high mount brake light.

  • Wiring Problems: Damaged or frayed wires can disrupt electrical flow. Inspect wiring for any visible signs of wear or damage.

Troubleshooting Steps

To effectively diagnose and fix your high mount brake light issue, follow these steps:

1. Check the Bulb:

- Remove the high mount brake light assembly.

- Inspect the bulb for any signs of damage or burning.

- Replace with a compatible bulb if necessary.

2. Inspect Connectors and Sockets:

- Look for corrosion or loose connections at the bulb socket.

- Clean any corrosion with electrical contact cleaner and ensure a tight fit.

3. Test the Fuse:

- Locate your vehicle's fuse box.

- Identify the fuse associated with the brake lights and check if it's blown.

- Replace with a new fuse if needed.

4. Examine the Brake Light Switch:

- Locate the brake light switch near the brake pedal.

- Check for proper operation by manually pressing the switch while someone observes if the high mount brake light activates.

- Replace the switch if it appears faulty.

5. Check Wiring:

- Inspect wiring leading to the high mount brake light for any visible damage.

- Use a multimeter to test for continuity in the wiring circuit.

Additional Tips

  • If you have access to a multimeter, you can check for voltage at the connector while someone presses the brake pedal. This will help determine if power is reaching the light assembly.

  • In some cases, especially with LED lights, ensure that they are compatible with your vehicle's electrical system, as incorrect voltage can cause them to fail.

  • If all else fails, consider consulting a professional mechanic who can perform more advanced diagnostics.

FAQs About High Mount Brake Light Issues

    • What should I do if my high mount brake light works intermittently?
      Intermittent operation often indicates a loose connection or a failing bulb. Check all connections and replace any faulty components.

    • Can I use LED bulbs in my high mount brake light?
      Yes, but ensure that they are compatible with your vehicle's electrical system to avoid issues.

    • How do I know if my brake light switch is faulty?
      If replacing bulbs and checking fuses does not resolve the issue, test the switch by bypassing it temporarily to see if that activates the light.

By following these troubleshooting steps and tips, you should be able to identify and resolve issues with your high mount brake light effectively.