Hello, are your switches locted above the raido assy?, If so, as in pic below. I am near certain the swich pane just snaps in. You should be able to use a small screwdriver to pop it out. I am pretty sure you do not need to remove the 2 lower screws to remove the trim plate first.
Each seat has a seperat control module under the seat. If you can see it looking under the front of the seat, you can try tapping on it. Kia doe not offer testing procudures for testing any heated seat circuit. You just have to have elecricl knowledge per say th probe various things for power and grounds. Below is diagram if you understand how to read one. This is what we would use to check power sources for the seat heaters. Each side is controlled seperate.