This car ('72 280SE 4.5) will run beautifully when it feels like it. The problem is some days when I get into it and put the key in I get absolutely nothing! No ignition lights,no power to the windows, zilch! I thought it could be the ignition switch, but I get no power to the headlights either. Unless the ignition switch and headlights are related in some way. I'm stumped, because some days it will crank right on and run perfect. It's not the battery because I had that tested. Any ideas? Appreciate!Thanks!