I replaced my factory radio with an aftermarket unit. The brake lights havent worked since then. I've been through two wiring harnessess and grounded to the chassis on one end and to the back of the radio on the other end. I finally have taken the aftermarket unit out and reinstalled the factory radio BUT the same things keeps happening. The #13 fuse blows every time I hook the battery back up after I replace it. This is a 1999 Ford Explorer Sport 4.0L manual transmission (pushrod). I know it's something I'm overlooking if anybody would be kind enough to point it out for me I'd appreciate it. I deliver pizza as a 2nd job and it's very unsafe for me to be driving around without brake lights.