I have a 2012 Ford Fusion that has sat for a few weeks and now it won't start. The dash lights do not come on, but all other lights, including the headlights and electronics work. The only light showing on the dash is the airbag light. I have been charging the battery because I think it is drained and checked it after a few hours and the car cranked slowly for about 5 seconds. Do these cars require a minimum voltage for the dash lights to turn on?