It will connect back of the head unit. You could explore this link and find some helpful info: http://www.clublexus.com/forums/rx-f...e-project.html
Read more: http://www.clublexus.com/forums/rx-1st-gen-1999-2003/706952-2001-rx-300-no-nav-cpu-video-input-nav-buttons-and-wiring-in-place-3.html#ixzz3ton8gElS