Its a safety feature so you cant watch dvds while driving only when the handbrake is up. I bypassed this on my old car by grounded the wire to a bit of metal, I could use it any time then but watch you dont get caught if you do that. Friends, here in Brasil we need to go with the car for checking every year at a state traffic dept and if they see a DVD player not connected to the hand brake the car isn't approved. We use to do this connection but also put a hidden switch to bypass it and permit the DVD use. So we only let the hand brake control over DVD when we need to do some inspection
