Brake light in car dash coming on

A car a friend of mine is driving is suddenly showing the "brake" warning light in the car dash. She says the brakes aren't squealing or grinding, but she has to use an unusually heavy amount of pressure to push the brake pedal down.

I haven't seen the car and don't know too much about cars, but it sounds as if she may be low on brake fluid. Am I way off base on this or is it something more serious.

The car is a 1994 Mitsubishi Eclipse I believe.

Anyone's useful advice is appreciated.
Thanks,
Steve If the light is red, then I would check the brake fluid first as you suggest. If the light is yellow, then I would suspect an electrical or anti-lock brake problem.
Keep us posted Good news up to this point "Trust". I checked the brake fluid resevoir and it was nearly empty. I put fluid in the compartment up to the "max" line and my friend has been driving the car without incident (red light coming on) since. It has only been a day, but I will continue to monitor the situation. Thanks for the advice.

I do have one question though. I don't know how long her car was running with the fluid as low as it was. Could this have caused any long-term, permanent damage to the brake system, particularly the master cyclinder?

Thanks again,
Steve Not likely that any damage occurred. Even if you run the master cylinder out of fluid it won't hurt it. You just loose brakes suddenly.

Lots of today's vehicles have a fluid level sensor in the master cylinder that will turn the red brake light on if the fluid is getting low.

Something to ponder, though... If the fluid was low, you either have worn brakes or a leak. I suggest a quick inspection of the brakes before it gets too cold out.....Car Repair Talk's forum.