Assuming you mean the red " BRAKE " light in your dash is lit :
That means that either your BRAKE FLUID LEVEL IS LOW in the brake
master cylinder or your parking / emergency brake is engaged
Maybe is the fluid brake that is low level.
If you mean the red " BRAKE " light in your dash is on , that means that the brake fluid level in the brake master cylinder located in your engine compartment ( on a Ford Taurus ) is LOW ( or that the parking brake is on )
If the " BRAKE " warning light in your gauge panel is on , either your parking / emergency brake is on and if not , YOUR BRAKE FLUID LEVEL IS LOW in the brake master cylinder located in your engine compartment
Air in the brake hydraulic system or defective master cylinder.
When anti-lock brake light comes on and goes off, it may be due to a malfunctioning wheel sensor. Another possible cause of this problem is a malfunctioning ignition switch.
Normally it means the master cylinder is low of brake fluid which also means your brake pads are worn out or you have a leak.
The red brake light on the dash means that the brake fluid is low or the parking brake is on.
check brake fluid level. and have a brake inspection . you more than likely have front brakes needing replaced.
The third brake light staying on could indicate a faulty brake light switch or a wiring issue, causing it to remain energized. When you open the door, the dome light activates, which may influence the electrical circuit, causing the third brake light to turn off. Once the door is closed and the dome light goes off, the brake light may turn back on due to the persistent wiring fault. It's advisable to check the brake light switch and related wiring for any defects or shorts.
you need a new brake pressure differential switch
if you mean the brake light on the dash... fill your brake fluid as it's probably low If you mean the brake lights outside the car, your switch is shorted and needs replacement, or you need to lift your foot off the pedal
Check brake fluid level Check to make sure emergency brake is fully released Check wire on switch of emergency brake (Maybe loose)