Just ordered the wiring diagram for the 2013 Mustang from Helm. It's over two inches thick on 8x14 paper! Wow are there a lot of relays in these cars! Spent about an hour looking through it so far to try to figure out the sound system wiring. I can't stand the stock sound system and i want to upgrade without permanently modifying anything. This is gonna take a while to plan out!
John
John