First remove the bezel around the door handle (is not absolutely necessarily but is easy to remove and it helps).
Then using a plastic flat tool (metal scratches), pull the rear of the switch assembly as forward as you can and then lift it. There is a spring-loaded clip that locks the switch in place. You should be able to do-it with bare hands garbing the back edge of the switch assembly and pulling forward and UP.
Unfortunately that is a 2002 STS and completely different switch assembly.
The heated seats buttons and track and PRND321 lights are indeed serviceable (actually heated seats not, that would classify as a switch rebuild).
Here is my interior (all replaced with white LED).