the biggest thing that causes brake fluid to turn "black" is high copper content. This is the result of your brake line deteriorating from the inside. when it is black you really should change it. the copper will start wearing out your rubber seals in your brake system, eventually resulting in.............................
NO brakes!!!!
Brake dust!
There is a brake fluid sensor located in the reservoir at the master cylinder. When the brake fluid is low it will turn the light on.
Fill the brake fluid...
It is not necessary to flush any system on a car. Brake fluid absorbs moisture from the air which in turn causes a corrosion to build in the system. That in turn will cause the cylinders to leak and not work properly.
Power steering pump worn, or low on fluid
The red brake light indicates that the parking brake is on or that the brake fluid is low. Be sure to add the specified brake fluid if you add fluid. Also make sure that you don't allow any dirt to get into the brake fluid and don't overfill the brake fluid either.
Low brake fluid.
Usually aerated fluid if it occurs when you turn the steering. If you're feeling a brake pulsation, look the the brakes for a problem.
Is the brake fluid level LOW in the brake master cylinder in your engine compartment ? If the brake fluid level is LOW that will turn the brake light on in your dash
Power steering belt is slipping, check that the belt is at the proper tension and that you power steering fluid is at the right level.
Check the brake fluid reservoir, with some vehicles they share the low fluid light and the e-brake light.
The brake fluid level may need to be topped off. Otherwise if the light is still on after checking the fluid, the ABS system should be checked by a professional. Be sure to use the type of brake fluid recommended on the brake fluid cap.