No, this not something you can buy aftermarket. "Dealer wants $600 to do the job", that would be parts AND labor to fix. The part is $345.00 from any Kia dealership. If you like you can send me a PM with the last 8 of your vin# and I'll see what I can do for a discount.
I took mine out last year when it started doing it, and cleaned it with electronics cleaner. Seems to have fixed it for now. Going on 3 months since it has messed up over the holidays when I cleaned it.
Cleaning it with electronics cleaner from a pressurized can should clean a lot/all of those up, and make the problem go away, at least in my case. I just let the can of cleaner basically pressure wash it, and let it dry, then reinstalled it.
Easy, cheap, and worth a try, before spending all of that money on a replacement part.
If it starts doing it again, I will take it back out, and clean it again, but may use my ultrasonic cleaner to see if it helps. (Or I may just take the shortcut and spray it again, depending on how long before I see the issue pop back up)