Where is the control pattern for 2012 cat 320D??
Serial number?
Not all of them had one. As I recall they were mounted in the radiator and battery compartment just forward of the batteries and and even with the bottom of the radiator.
My 314D is electronic, and accessed via the monitor. Again, serial number is needed.
So, I picked a random 320D. The diagrams below show the electronic pattern changer manifold. The pattern is toggled through the display monitor controls. All four circles surround the same manifold.