EE WAS TRAMMING THE BOBCAT WHEN A FAULTY SAFETY SWITCH CAUSED THE HYDRAULICS TO LOCK UP WHICH SET THE BRAKES, CAUSING THE BOBCAT TO STOP IMMEDIATELY AND UNEXPECTEDLY. THE SUDDEN STOP CAUSED TH E OPERATOR TO HIS HIS HEAD INTO THE TOP OF THE CAB. NOTE: WE WERE NOT INFORMED THAT THIS EE WAS ON RESTRICTED DUTY UNTIL 2/2/4 EVEN THOUGHT THE RESTRICTIONS BEGAN ON 1/20/4.