The headrests stopped working on both front seats. Opened the seatback and the mechanism that moves the headrest up and down cracked on both. They're plastic and I tried super gluing/epoxying them back together. Unfortunately, they re-cracked upon moving the headrests up and down again. My question is: I know I can/will buy the new parts for the sliding mechanism BUT I want to know if there is a power cutoff (solenoid?) once the mechanisims reaches the final down and final up positions (I believe the sunroof/power windows have this type of cut-off to prevent burning the motor/breaking the mechanisms?). My concern is that if I simply replace the plastic parts (which seems easy enough), the motor will rip them apart again after reaching the full up/full down position, when in fact there is a cutoff switch that also needs to be replaced. (I don't believe the parts broke because of someone yanking on the headrests.) Thanks. By the way, it seems pretty weak to use plastic parts to hold the headrests in place (for my situation and in any type of accident, for example)