Do you have field tracker or only ahhc? Either way you need to change the potentiometer on the head to work on a 2300 series from a 1600 series. May want to go to the new style cable if you haven't already. Good luck.
If your potentiometer is black you will need to change it for the correct one, smaller size with the transparent back and you will need to change the mount plate too to accomodate the alignment pin on the new pot to adjust it properly.
Read your manual, you have to calibrate the "pot" on the header to the combine before the system will work properly once the correct sensor is installed.