I have convinced my self that in 1955, a backup light was intended for you to be able to see back there, in the dark.    So it only lit up at night, if the headlight switch was on, and you were backing up.  Am I correct?  Since then safety concerns now make the backup light come on anytime the transmission is in reverse, day or night.  Am I correct.  The power for my b/u switch (automatic transmission) is hot when light switch is on (in park or headlights).  I thought I found another wiring error.