How does the 3rd brake light work?

In North America, since 1986, all vehicles feature a third brake light. Like stop lamps at the corners, the CHMSL indicates when the driver is braking, but its position and function add an extra layer of safety. Positioned higher than the corner stop lamps, the third brake light is more visible to other drivers.

Does a truck need a 3rd brake light?

Federal law mandates that all vehicles have the third brake light outfitted within the car. Additionally, the third light must be comparable to the other brake lights on the vehicle so that it is not distracting to the drivers behind the vehicle.

What to do when your third brake light is not working?

When the lower lights do not come on and only the third-brake light works, the brake-light switch may be ruled out. Again try the emergency-flashers to check for wiring, socket and lamp problems. If the flashers work, check for blown fuses as a few vehicles use separate circuits for the lower and third brake lights.

When does the brake light switch show continuity?

Using the wiring diagram, we can determine which leads should have continuity and when. The brake-lamp portion of the switch will show continuity when the brake pedal is depressed. When we release the brake pedal, it returns to the up-position. In this position, the brake light switch changes to an open-circuit.

What causes brake lights to go out but lower lights work?

If the plunger of the switch does not contact the pedal, check for an adjustment. In rare instances, the brake booster may fail, and the pedal will not rise enough to contact the switch. Pull up on the brake pedal and if the lights go out, switch mis-alignment or pedal position error is the likely cause.

Can a bad brake light cancel a turn signal?

With a bad turn-signal switch, the third-light should still function. On this type system, the turn signals and brakes use the same circuit. When we use the turn signal switch, it cancels the brake light signal, on the side selected.

When the lower lights do not come on and only the third-brake light works, the brake-light switch may be ruled out. Again try the emergency-flashers to check for wiring, socket and lamp problems. If the flashers work, check for blown fuses as a few vehicles use separate circuits for the lower and third brake lights.

Why are my brake lights not working on my 1997 Chevy?

Pull the plastic cap off the fuse chassis and you’ll see a square relay fuse switch and replace it for the brakes. It’s only $13 bucks and is the predominant issue with 1997 Chevy Trucks and the brakes not working especially if you reverse and blinker lights do work. Was this answer helpful? Its the taillight circuit board or a broken wire.

Using the wiring diagram, we can determine which leads should have continuity and when. The brake-lamp portion of the switch will show continuity when the brake pedal is depressed. When we release the brake pedal, it returns to the up-position. In this position, the brake light switch changes to an open-circuit.

Why are the brake lights not working but the tail lights are?

Blown out light bulbs are the most common reason for why the brake lights not working but the tail lights are. Remove the screws from the bulb lens (which you can access through the trunk or see your vehicle repair manual to get the exact location). Push the bulbs and turn them counterclockwise to remove from the socket.