My reverse lights will not work at all on 2002 Oldsmobile Bravada

I checked the fuse and it is ok, i also checked the bulbs which are also ok. I checked to see if there was power going to the tail light "reverse Light" and it did not show any signs of current. My turn signals and brake lights work fine..

Asked by for the 2002 Oldsmobile Bravada
poss grd issue or signal from the trans range senor