Help with navigation control
 

I am in the process of bulding my carputer.

So far i installed:

Auxmod
Computer
Xenarc 700TSV in navigation monitor

Now, I find it a little bit difficult and lot of dangerous to use the touchscreen panel.

Instead of the touchscreen i thought to use the OEM navigaiton controls and "hack" it with a joypad.

Therefore i am asking help on the wire harness (see attachment) of the navigation control buttons.
Could i just short those wires to the joypad and which is which?

Any feedback is appreciated