1998 Cadillac STS back up lights

My back up lights and license plate lights and tail lights that are located on the trunk lid wont work while the car is on, however they do light when I unlock the car , so the bulbs are good. I've checked the fuses unless I'm over looking one


updated 2/7/09

Thank You for you input , however after digging into it deeper a cut wire was located.

Thanks Again!