There are two files related to AI sensors: AI_Sensors.dat in Data\Library and Sim.cfg in Data\Cfg. For the first you'll need S3D Editor, for the latter Ye Olde Windoze Notepad. I also recommend reading
this excellent thread, as well as
this one, both by Ducimus, on how the AI sensors work. They're quite old, but the gist is still there.