1. Open the trunk.
2. Remove the socket by turning it counterclockwise until the tabs on the socket align with the slots.
3. Remove the bulb from the socket by pressing it in and rotating it counterclockwise until the tabs on the bulb align with the slots in the socket. Pull the bulb out of the socket.
4. Insert a new bulb by inserting it into the socket and rotating it until it locks into place.
5. Install the socket in the assembly by aligning the tabs on the socket with the slots in the assembly. Push the socket into the assembly and turn the socket clockwise.
Hyundai Elantra AD (2016-2020) Owners Manual: Detecting Sensor
The rear radars are located inside the rear bumper for detecting the side and
rear areas. Always keep the rear bumper clean for proper operation of the system.
NOTICE
The system may not work properly when the bumper has been damaged, or
if the rear bumper has been replaced or repaired.
...
Hyundai Elantra AD (2016-2020) Owners Manual: Anti-lock Brake System (ABS)
WARNING
An Anti-Lock Braking System (ABS) or an Electronic Stability Control (ESC)
system will not prevent accidents due to improper or dangerous driving maneuvers.
Even though vehicle control is improved during emergency braking, always maintain
a safe distance between you and objects ahead ...