Abs brake failure. abs activates during normal operation of vehicle breaking, pedal gets hard and or vibrates, brakes still work but you must apply very hard force to pedal. vehicle is a 2004 chevy colorado with only 30,000 miles. this has been occurring on and off for about three to four months. it appears that it becomes worst during wet humid weather, and when turning and braking at the same time. occurrences have increased in frequency from a couple of time a week to several times a week. i had not taken the vehicle into mechanic to be checked yet, but will soon. also abs fault light came on a couple times and stayed on until vehicle was shut off, and restarted much later, at which time the light reset. this has occurred a couple of different times during the last two months. *tr