You may still have air in the system, also check to make sure the brake fluid level sensor in the brake fluid reservoir is plugged in and working.
If you mean the " BRAKE " light in your dash , that means your brake fluid level in the brake master cylinder is LOW . The brake master cylinder is located in the engine compartment on the drivers side
The one on the master cylinder is the brake light switch. The one on the brake pedal is for the automatic transmission, assuming that the car is automatic.
It is threaded into the master cylinder. If you can't reach from under, remove the fuel tank to expose the master cylinder and brake light switch.
The dashboard brake light usually indicates a differential pressure malfunction between the two sides of the master cylinder, or that the emergency brake is on. Check the emergency brake, then check the master cylinder. You may need to bleed the brakes. You may need to reset the master cylinder, although they usually reset by themselves.
May be a bad master cylinder, a bad sending unit from the master cylinder or the parking brake or the parking brake is not completely disengaging.
The brake light in the dash comes on if the parking brake is engaged or the brake fluid level is low in the brake master cylinder in the engine compartment
If your handbrake is on or if the brake fluid level in the brake master cylinder in your engine compartment is LOW , the " brake " light in your dash will light up
The brake light switch is threaded into the master cylinder. Open the hood, look at the brake master cylinder, notice the brake light switch with wires connected. Have new one ready to install when you remove the old one to keep loss of brake fluid to a minimum.
You ONLY lose brake pressure if you have a leak somewhere ! - This can be in any wheel cylinder , the master cylinder, or a fractured brake line. Till you find the leak, keep your master cylinder topped up daily.If the brake fluid reservoir remains full and the brake pedal sinks to the floor as you are waiting at a stop light, the master cylinder is at fault.
Above the brake pedal where the master cylinder is attached to the brake pedal assembly.
Is the brake fluid level LOW in the brake master cylinder in the engine compartment ?
If your brake light is on , either the parking brake is on or the BRAKE FLUID LEVEL in the brake master cylinder in your engine compartment IS LOW