I just installed an FM-750 in a spreader truck. I used a 12 pin Deutsche socket. I found links online telling you have to connect the 10 pin to the 11 pin to activate the mapping.
I went into the menu under coverage logging and chose switched. I also found a Trimble part # for a switch with a plug. ZTN60477S. I see that Case dealers stock these but can't find price or availability on the weekend.
I connected the 11 pin the the 10 pin to an on and off toggle switch. It will not activate the coverage mapping, but the touch screen on and off still works in "coverage switched" mode.