Cannot say without a model number.

Could you give more info on what switch you are referring to.

Most modern unit ovens are controlled by an electronic control board.
On some units there is a separate control panel/keyboard which feeds into the control board.
Also on some units there is a thermal fuse that kills power to the oven elements if the temperature goes too high. Thjis can be blown by a number of things.
1. Sometimes a self clean cycle will blow it.
2. A faulty oven sensor
3. A blown control board

I personally do not have access to tech info on Thermador units.
Note that getting parts cvan be a problem with older units.

Below is a link for some manuals.
http://appliancejunk.com...?action=downloads;cat=21

There are a couple manuals for dual fuel units.
Nothing for a Thermador but at least it will give you an idea how these units are usually wired.

You will have to join the site and be logged in to be able to download any manuals.