Have a look at the manufacturers website in the 'parts' section. They have exploded diagrams to identify the various parts and they also give you an idea where items like micro switches are located.
Log onto www.thetford.com click on 'parts' then click on 'permanent toilets' then select your model to bring up a PDF of your diagram and parts
You can even download a manual--just click on the 'Manual' tab and click your model.
seemples!!
Geoff, deep down inside Wales, August 2010