Automatic? My reverse lights wouldn't work because someone removed, and never replaced, my backup light switch on the trans housing (4spd manual). And UConn is right. Good grounds are so important. Something I found (the hard way, duh) is when you remove a ground and paint under it, then replace with new hardware, could lose ground contact. Run a wire direct to your neg battery terminal to the ground on your lights. At least you'll rule out, or confirm, a ground issue.
'68 400HO Coupe, 4 spd, 259 interior, Windward Blue. My other car's a Johnson 15 outboard on a '61 Starcraft rowboat... Just sayin'.