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: Starter Relay Repair procedures
Inspection
1.
Turn ignition switch OFF and disconnect the negative (-) battery cable.
2.
Remove the fuse box cover.
3.
Remove the starter relay (A).
4.
Using an ohmmeter, check that there is continuity between each terminal.
TerminalContinuity30 - 87NO85 - 86YES
5.
Apply 12V ...
Hyundai Sonata LF 2014-2019 Service Manual: Seat Heater Switch Schematic Diagrams
Circuit Diagram
...