* Burned-out bulbs: This is the most frequent cause. Check all three brake lights (two on the rear and one on the high-mounted stop lamp, often integrated into the rear window). Replace any bulbs that are not working.
* Blown fuse: The brake lights are controlled by a fuse. Consult your owner's manual to locate the fuse box and identify the fuse for the brake lights. Replace the fuse if it's blown (check for a broken filament).
* Brake light switch: This switch is located near the brake pedal and activates the brake lights when the pedal is pressed. A faulty switch can prevent the lights from working. This often needs professional diagnosis and replacement.
* Wiring problems: Worn, damaged, or corroded wiring can interrupt the electrical circuit to the brake lights. This often requires a mechanic to locate and repair the damage.
* Brake pedal position sensor: Some newer vehicles use sensors to determine brake pedal position. If the sensor malfunctions, it may not send the signal to turn on the brake lights.
* Central Tail Light Control Unit/Body Control Module (BCM): A more sophisticated fault could lie within a central module that controls the various lights. This would require diagnostics to identify.
Troubleshooting Steps:
1. Check the bulbs: This is the easiest and quickest check.
2. Check the fuses: Refer to your owner's manual.
3. Test the brake light switch: This can be tricky and might require some technical knowledge. A simple test might involve using a test light to see if power is reaching the switch when the brake pedal is pressed. If not, it's likely the switch.
4. Inspect the wiring: Look for any obvious damage or corrosion in the wiring harness leading to the brake lights.
When to seek professional help:
If you've checked the bulbs and fuses and the problem persists, it's best to take your Toyota to a mechanic or qualified technician. They have the tools and expertise to diagnose more complex issues like faulty switches, wiring problems, or issues with the central control modules. Driving with non-functional brake lights is dangerous and illegal.
