Hyundai Sonata LF 2014-2019 Service Manual: Head Lamps Repair procedures
Inspection
1.
Check the battery voltage. (Low beam will be on when the battery voltage above 9V.)
2.
Check the fuse and relay.
3.
Check the polarity of ballast. (If the polarity are changed, low beam doesn't lighten)
4.
Check the bulb connector securely.
5.
Visually bulb checking ...
Hyundai Sonata LF 2014-2019 Owners Manual: Smart key precautions
The smart key will not work if any of the following occur:
The smart key is close to a radio transmitter such as a radio station or
an airport which can interfere with normal operation of the transmitter.
The smart key is near a mobile two way radio system or a cellular phone.
Another vehicle ...