The high-pressure cooling system has a reservoir filled with year-round antifreeze coolant. The reservoir is filled at the factory.
Check the antifreeze protection and coolant level at least once a year, at the beginning of the winter season and before traveling to a colder climate.
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: Distributing the sealant
11. Immediately drive approximately 4~6 miles (7~10 km or about 10 minutes) to
evenly distribute the sealant in the tire.
Do not exceed a speed of 50 mph (80 km/h). If possible, do not fall below a speed
of 12 mph (20 km/h).
While driving, if you experience any unusual vibration, ride disturbance ...