2000 Pontiac Grand Am ABS Brakes

Going in blind here. Did you replace any front wheel parts lately like bearings, hub assembly or brakes?
Sounds to me like a wiring problem straight from the factory. The sensor, if wired correct will apply the ABS when certain pressure is applied at certain speeds which stop your brakes from locking up. If the ABS wiring harness is wired incorrect it could sending the computer a message to apply ABS all the time. However, if you did not replace any pars, I suggest it could be a sensor gone bad. This could be either in the front or back. Good Luck