I'm totally puzzled. My Comanche is a 1988 and when I turn on the headlights, the tail lights and running lights don't come on, but when I put my foot on the brakes they do come on. Also when I'm towing my trailer, the trailer running lights don't come on unless I put my foot on the brakes. It's not a fuse and I just replaced the switch clearly not the switch. Where is the ground so I can check it next?