Rear lights or tail lights, are an important safety feature on your vehicle, especially when driving at night or in bad weather. These lights let other drivers know where you are on the road and illuminate brighter to indicate when you are braking. If you notice an issue with your rear lights, you should have it inspected immediately.
How this system works:
During the day time, or when the headlights are off, rear lights only illuminate to indicate when a driver is braking. At night, or when the headlights are turned on, the rear lights illuminate constantly to let other drivers know where you are, and illuminate brighter when braking. Your rear lights are controlled through the same switch that controls the headlights. Power is channeled through a relay to the rear lights, illuminating them when the switch is engaged. A brake light switch, which is typically connected to the brake pedal, illuminates the brighter brake lights when the brake pedal is pressed.
Common reasons for this to happen:
- Blown Fuse: As a first resort, a mechanic should expect the corresponding fuse for your rear lights. When a fuse blows, it prevents the circuit from completing, in this case preventing the rear lights from illuminating. Sometimes when a taillight lens cracks or breaks, it can allow moisture to enter the lens and cause a short circuit, blowing the fuse.
- Burned Out Bulbs: In the case where only one of your rear lights appears to be out, the cause is most likely a burned out bulb. When the filament breaks inside a bulb, it cannot illuminate the gas inside the bulb. A burned out bulb will not affect the circuit of the entire rear light system, and the other rear light should continue to function normally.
- Faulty relay: A relay transfers power from the battery to the lights themselves, but when a relay fails, the connection is unable to be completed. A relay may also fail because it is not grounded properly. A wire that is not grounded properly is unable to protect the circuit and provide an outlet for excess charge that build up. A vehicle with a bad relay or bad ground may not be able to successfully power your rear lights.
- Faulty Brake Light Switch: If the rear lights illuminate normally but do not become brighter when braking, the brake light switch may not be functioning properly. The brake light switch circuit is completed when the brake pedal is pushed, but if the switch has been pushed out of place or is not connecting properly, the brake pedal may not be able to complete the circuit, meaning that the lights will not illuminate.
How important is this service?
Tail and brake lights are designed to help other drivers see you on the road and if they are not working, you may be at an increased risk for an accident. If you notice your tail lights have gone out, or are not working properly, you should stop driving the car and have it inspected as soon as possible.