brake lights come on and go off

I have a 2004 Malibu and the brake lights come on and go off while i'm driving Just wanted to know where the problem is.

Response:
That Dash Light "BRAKE" doesn't always indicate a problem. If your Parking Brake is loose this light may flash as you drive or even remain on. If this light ONLY comes on while Applying the Brakes THEN you have a problem of either adjustment/replacem ent or Air in the system. A GOOD Indicator is if you must "Pump Up" the Brakes. This Light is controlled by a Proportioning Valve and NOT Cheap and Rare to go Bad.