I just bought the Direct Wire Smartcord and the Add-A-Circuit, and am wondering where to plug it into the fuse box. I have a 2009 Mercury Mountaineer. I I have 2 empty Fuse slots and just want the radar to turn on when ignition is started. I have seen the videos but have no idea where to use the fuse. The cigarette lighter is a constant source so I cannot do that. Anyone who can provide exact placement I would truly appreciate.