The vehicle's front and rear seats have adjustable head restraints. The head restraints provide comfort for passengers, but more importantly they are designed to help protect passengers from whiplash and other neck and spinal injuries during an accident, especially in a rear impact collision.
WARNING
To reduce the risk of serious injury or death in an accident, take the following precautions when adjusting your head restraints:
NOTICE
To prevent damage, NEVER hit or pull on the head restraints.
Hyundai Elantra AD (2016-2020) Service Manual: Components and Components Location
Components
1. Rear seat back assembly [LH]2. Rear seat back assembly [RH]3. Rear back armrest4. Rear seat cushion assembly
...
Hyundai Elantra AD (2016-2020) Service Manual: Components and Components Location
Component Location
1. DDM (Driver Door Module)2. ADM (Assistant Door Module)3. RRDM / RLDM (Rear Door Module)4. Front window motor5. Rear window motor
...