96 2500 Silverado

Hi Guys I'm New To This Whole Internet Thing, But I Really Need Help. My Husbands Ford Has To Go In The Shop So He Needed To Borrow My Truck, He Owns His Own Landscape Busness So He Needed To Hook Up The Towing And Lights For The Trailer. Well I Dont Know What He Did But I Have Tail Lights And Turn Lights And Back Up Lights But No Brake Lights. I Replaced The Fuse And Checked All The Others But I Cant Find Why The Brake Lights Dont Work. Any Advice You Have Would Help, Except For Loaning Him The Truck That Won't Happen Again. Thanks

I'd say there is probably a bare wire grounding out on the frame or something.