How to enable "tank mode"?

Hello. My university just got their DK2 last week and I have been trying to create a small prototype for my advanced game technology course. I want to let the players choose between "walk where you look" and "tank" mode. I'm using Unity and have been able to figure out how to decouple the forward direction from the head and apply it to the body instead enabling me to move in the direction the body is facing. However, I have a problem. I have been reading through the code but am unable to figure out where the mouse input is applied to the head movement. I wish to remove it and apply it to the body instead.

Could someone please point me in the right direction?