A 2015 FORD EXPLORER WAS INVOLVED IN A HIGH SPEED SIDE-IMPACT AND ROLLOVER COLLISION. THE SEATBELT WAS WORN AT THE TIME OF THE COLLISION BASED ON A PREPONDERANCE OF PHYSICAL EVIDENCE ON THE OCCUPANT RESTRAINT SYSTEM AND INTERIOR VEHICLE COMPONENTS. THE ACM REPORTED THE DRIVER WAS "NOT BUCKLED" AT THE TIME OF THE COLLISION. THE PRETENSIONER DID NOT FIRE. THE BUCKLE ASSEMBLY WAS TESTED AND THE BUCKLE SWITCH APPEARED TO BE FUNCTIONING PROPERLY. AFTER THE IGNITION WAS CYCLED TO "ON" FOR APPROXIMATELY 1 MINUTE AND 10 SECONDS, THE SEATBELT WARNING LAMP ILLUMINATED AND DEACTIVATED PROPERLY WHEN THE LATCHPLATE WAS INSERTED AND REMOVED REPEATEDLY. AFTER 1 MINUTE AND 10 SECONDS, THE SEATBELT WARNING LAMP WOULD ILLUMINATE AND DEACTIVATE SPORADICALLY AS THE LATCHPLATE WAS INSERTED AND REMOVED.