How do you test out a brake light?
One wire will control the power that goes into the brake lights while another wire controls the power that goes out of them. Take your LED sensor and place it on one of the two wires in your brake light. Hold the brake pedal down while you do this. Then test out the next wire.
How does the brake light circuit work in a car?
A typical brake light circuit The most common brake light switch is the simple mechanical type mounted close to the brake pedal arm. When the pedal is depressed, the switch automatically closes to turn on the brake lights. The other type of switch works hydraulically and is operated by the pressure of fluid in the pipes when the brake is applied.
What happens if you have a bad brake light switch?
The brake light switch on modern vehicles is no longer a simple switch used to turn on the brake lights. A bad brake light switch, for example, can trigger the ABS and traction control lights, but it can also prevent engine start or even transmission shifting. In this article, we go over the symptoms of a bad brake light switch and test them.
Where is the fuse on my brake light?
If your lights don’t illuminate on either side and your brake light switch is good, then the next thing to check is the brake light fuse. Locate your vehicle’s fuse box, which is usually under the hood or on the kick panel inside the passenger compartment.
How do you check the brake light circuit?
Check and clean up the earth side of the circuit. If the test lamp fails to light, next check if current is reaching the fuse by probing each fuse terminal in turn with the test lamp. If the lamp lights on the battery side of the fuse, the fault is in the fuse itself.
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.
What causes the brake light to come on?
The brake lights should now come on. If both terminals cause the lamp to light, the fault lies in the wiring between the switch and the brake lights. This should be checked along its length for any breaks or chafing where it could short circuit .