Not sure if what you're saying you tried is this, but here's what worked on my '14 - Sit in the seat with the truck off, buckle the seatbelt, turn key to ON (not start) and wait for seat belt light to go off, then within 10 seconds unbuckle and rebuckle the belt 3 times (ending with it unbuckled, if I'm not mistaken), then turn the key to OFF.