Car or Truck Brake Lights Not Working? How to Diagnose Tail Lights

Summary

This video provides a comprehensive guide on diagnosing and fixing brake light issues in vehicles. It emphasizes the importance of checking individual bulbs, fuses, and the brake light switch, detailing methods for testing each component. Viewers learn to identify common problems, such as blown fuses or faulty connections, and how to use tools like test lights and jumper harnesses for troubleshooting. The video encourages viewers to be proactive in vehicle maintenance, offering valuable tips to ensure their brake lights function properly, enhancing safety on the road.

The video is abnormal, and we are working hard to fix it.
Please replace the link and try again.

Q & A

What should you check first if your brake lights are not working?

Start by determining which brake lights are out—whether all, one, or specific lights like the third brake light.

What could cause only one brake light to be out?

The most likely cause is a blown light bulb, but it could also be a blown fuse specific to that side.

How can you check the fuses for the brake lights?

Remove the fuse and inspect it for burn marks, or use a test light to check for power on both sides of the fuse.

What should you do if the fuses are good but the brake lights still don’t work?

Check for potential issues with wiring, bulb sockets, or corrosion, especially in trailer wiring.

How can you test the brake lights if you're alone?

Use a pry bar to hold the brake pedal down while you check the lights.

What should you look for when inspecting the brake light bulb?

Examine the connections for corrosion and check if the filament inside is broken or damaged.

How do you test the third brake light's wiring?

Use a test light while someone pushes the brake pedal to check for power and ground on the two wires.

What indicates that the brake light switch might be faulty?

If the brake lights work when bypassing the switch with a jumper harness, the switch is likely bad.

How can a scan tool assist in diagnosing brake light issues in newer vehicles?

A scan tool can show live data when the brake pedal is pressed and may reveal fault codes related to the brake pedal switch.

What are potential issues with the body control module regarding brake lights?

Problems could include programming issues or internal faults that prevent the module from signaling the brake lights.