I was at a stop light when I heard 2 pops. Turned around and noticed driver and passenger headrests were split apart in the middle. Got home and looked in the owners manual and it said that the active headrests will activate if a rear collision is sensed. I wasn't rear ended nor did I back into anything. Any advice on how to repair the 2 headrests without taking it in to the dealer and having them charge me $$$$$ to fix them? Thanks