One problem related to alternator/generator/regulator has been reported for the 2013 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2013 Hyundai Sonata based on all problems reported for the 2013 Sonata.
Both headlights and break lights continue going out. First time I replaced the break lights, they had melted to the unit. I have had both headlights go out at the same time on two separate occasions. I have replaced the alternator twice now and it is looking like I will have to replace it again soon, headlights are getting dull (it's hard to see, and my brights won't click on (it is not the blinker column)), the battery has been replaced when the alternator was replaced as well. This is getting expensive. The dealership told me it was the blinker column when it was actually the alternator. Replacing the lights have been happening for years, the alternator problem started last year, so within 2 months of replacing it the first time, it went out again, and now 5 months later, it is needing to the be replaced again. It appears that it is perhaps an electrically issue since lights, battery, and alternator are going out.