OK I read online that just grounding the green brake wire doesnt work anymore so now you have to use a toggle switch or something heres what someone said : "u cannot just ground the green wire(wont work) u need to get an SPST switch...any radioshack will have it... tap the green wire into one side and the other to ground(top of in dash works fine too) and just switch when u want video. like a mini parking brake...very easy" my question is how exactly do i ground it after i have the green wire on one side of the switch? do i need a seperate wire to ground it?