back up lights

need some help,i have a 1980 f100 truck and its almost time for inspection and cant seem to get my back up lights to come on,,i checked the bulbs they seem ok ,,is there something else i should be check,,any info would help,,,thanks :evillol:

There is a back up light switch on the truck. Not sure, but I think it is on the transmission. A lot of times they incorperate these in the neutral safety switch.