Product review (5 stars): If your Samsung dryer is not heating, but everything else seems to be working, try replacing the Thermistor FIRST
I had a dryer that spun but didn't heat. I called two idiots to come look at my dryers (was charged the call-out fees, $50 for one and $60 for the other), both took my dryer apart and tested a bunch of stuff. It looked legit because they had a multi-meter. The first guy said it was my main control board that was the problem. So I bought a new one for like $120 bucks replaced it myself and still the dryer would not heat. That's when I called the second guy and he said it my was outlet that was the problem. I mean seriously dude? I paid him to go away essentially since he was already inside the house.

After a bunch of googling, I saw that people were replacing their Thermistor and fixing the issue. An $8 dollar fix. So I had nothing to lose, I'm already $200+ deep in this repair what's another $8 bucks. I figured out how to take apart the dryer on youtube, the model was not exact but close enough. It's not difficult to do, but you do need to take apart the dryer. I would rate it a medium difficulty and give yourself an hour to do it. The hardest part for me was replacing the belt correctly. Anyway, this fixed the heating problem and I am a happy customer.

TL;DR I would recommend replacing the thermistor FIRST before calling people to come do a diagnostic on your dryer or attempting to replace other stuff.