What is the rocker switch called that you can turn it on auto or manual and controls the thermostat?

Hi! dwaynedavis5061, welcome to AMHD :)

Check here:
mobilehomerepair.com/NordyneGas (http://www.mobilehomerepair.com/NordyneGas.html)

Its alphabetical scroll down to switches.

Here's the manuals page:
hvacmanuals.com/ (http://www.hvacmanuals.com/)