Given that it’s essentially an intermittent problem, I might have to do that every night and day for a week or more. My inclination at this point is to pony up and drop it off at the dealership. If indeed it’s a flaky BCM, as @Tester suggested, it’s way over my head.
My experience with the dealerships has mostly been that if there is no code, they can’t figure it out and they just throw random parts at it. Unless, this is a common problem, which it would already have a TSB and some posts on the Hyundai forum about it.
We just had a similar issue with our Sonata where after I changed the steering coupler, the HVAC and wipers stopped working. The dealer wasn’t even close to a solution and only kept the car for one week. It was the same connector that I had doubts about-just didn’t want to man-handle it.
That being the case, since it’s no longer under warranty I might as well let our regular independent mechanic take a shot.
Dealers vary, at work whenever the mechanic could could not figure it out, even on a 15 year old truck with no codes, the dealer fixed it every time.