Driver's side reverse light not working

[RustyPile]

Originally Posted by slowboy

1972 GMC CUSTOM 1500

<<<<<<<SNIP>>>>>>>Checked bulb and it's fine

Took bulb housing out and looks like only one wire going to socket

How/what do I do next please

Thank you,
Keith

First -- How did you check the bulb??

The backup light circuit is a one wire circuit.. The socket, housing, and bed all work together to form the ground path.. Unlike the brake light circuit, if one backup light works, all switches and the fuse that are in the circuit are operational.. If you have voltage at the non-working backup bulb socket, then you have a ground path problem. If you don't have voltage, there is a break between that socket and where the wire divides for each light.