some units need a sequence like on/off/on/off or some like the jensen need a relay. I put a toggle on my Clarion 765

 

i took the e-brake wire and put a toggle between it then grounded. Used the green wire on the regular brake for the other connection. Worked like a charm, thanks guys

 

other then the avic n2 all the screens i have installed i have simply twisted that parking break wire in with the rest of the grounds and it works fine. from what my dealer told me about the n2 there is a chip that need to be replaced,removed, or reprogramed or something in the unit itself. it wont hurt anything but if you ever need to send it to pioneer for repair they will not warrenty the unit if it has had this mod done. my dealer charges me 75 bucks to do this mod when i buy one of the n2's from him