I have a 1969 Ford LTD and i am having a problem with my reverse lights. I have already changed the light bulbs and the fuses and both of the reverse lights still do not work.
Check the switch on the transmission where the linkage attaches.
That switch is what turns on the reverse lights.
Tester
Have you checked the switch that turns them on? I’m not sure where it is on this car. Probably near the base of the steering column for a column shift automatic or in the floor shifter for a manual or console automatic. Also check the grounds for the lights. Old cars like these have many rusty ground connections. Take out on of the new bulbs and while is is in reverse (not running!) and check for ground and 12v at the socket. 12v with no ground, you have a bad ground connection. No 12v but a good ground, go to the backup light switch. Good Luck.