N Hodges,

Assuming that your S350 is anything like my 400SE, I can answer a couple of your questions based on my recent experience.

There is a twist-out light bulb for the ambient temperature display. The best way to get the instrument cluster out is to remove the LH vent, reach in, and push the cluster out from the back.

Unplugging my instrument cluster did not generate any DTCs. Out of curiousity, I did start the engine with the cluster out and everything worked pretty much as usual.

It sounds like instrument cluster removal and a few light bulb changes will do the trick for you.

Ed