* Faulty Brake Light Switch: This is the most common culprit. The switch is located near the brake pedal and tells the car when the brakes are applied. If it's sticking or malfunctioning, it can keep the brake lights on even when the pedal isn't pressed.
* Short Circuit in the Wiring: A short circuit in the wiring leading to the brake lights can also cause them to stay on. This could be anywhere from the switch to the lights themselves. Damage to the wiring harness from age, wear, or rodent activity is possible.
* Faulty Brake Light Bulb: While less likely to *keep* the light on after the car is off, a very faulty bulb can sometimes cause a short.
* Problem with the Brake Pedal Position Sensor (if equipped): Some models have a sensor that monitors brake pedal position; a malfunction could send a false signal. This is less common than the brake light switch.
* Body Control Module (BCM) Issue: The BCM controls many electrical functions in the car. A malfunctioning BCM could be sending the wrong signal to the brake lights. This is less likely but possible.
Troubleshooting Steps:
1. Check the brake light bulbs: Make sure they're not blown. A blown bulb *might* cause a short, but it is unlikely to keep the light on after shutdown. Try replacing them anyway as it's the cheapest and easiest step.
2. Inspect the brake light switch: If possible, visually inspect the brake light switch for any signs of damage or corrosion. You might even be able to gently press it to see if it feels stuck. This requires some mechanical aptitude and may necessitate removing a cover or parts to access.
3. Check the wiring: This is more challenging. Carefully examine the wiring harness running from the brake light switch to the lights for any signs of damage, fraying, or exposed wires.
4. Consult a Repair Manual: A repair manual specific to your year and model Mitsubishi Galant ES will provide detailed diagrams and instructions for troubleshooting the brake light circuit.
5. Professional Diagnosis: If you're not comfortable working on the electrical system yourself, take your car to a qualified mechanic for diagnosis and repair. They have the tools and experience to pinpoint the problem effectively. Leaving the brake lights on constantly will drain your battery.
Leaving the brake lights on continuously will drain your car battery, so it's important to address this issue promptly.
