where are the brake sensors located on the 1997 chevy cavalier

Dear Renee-- Oftentimes a sensor willk give you a false reading. But since you add that the brake pedal on your 1997 Chevrolet Cavalier often goes to the floor, I would say the sensor is doing its job and you do indeed have a brake problem. Maybe it is the master cylinder. Maybe a damaged hose is leaking brake fluid. It could be several things. But since I do know that driving a car with bad brakes means trouble, have it looked at right away. Good luck from Bovan.