Reverse lights dont work

I have a1996 plymouth voyager mileage 132000 6 cylinder.I went to get it inspected they said reverse lights don't work.I checked the sockets they work, I checked bulbs they work, all the other lights on the tail light work except reverse lights on both sides.I thought maybe it was a fuse but I looked and cannot find a place in the fuse box for reverse/back up lights. If it is listed seperately in the fuse box under a different listing please let me know?Also could it be something else, I heard about a trans axle range sensory?If it is something like a sensor is it repairable for me to do at home?Thank you
serena