Yes, it has the be set and the NNBS have some sort of circuit so you can't just jumper the wires so it sees a set parking brake. This has a circuit that mimics that signal. I tried playing a DVD before and it would say it was illegal to watch video in the front seat while moving and I needed to set the parking brake. Now it just says to hit "OK" if I've set the brake, released it, and set it again. Then the movie plays. Not sure why it wants me to set it twice but the bypass works. It's a super simple setup- one wire to ground, one to the amp turn-on and one to the park brake wire going into the HU.What does that do? Does the parking brake normally have to be set to get the deck to display video?