Driver's side reverse light not working

[slowboy]

1972 GMC CUSTOM 1500

Replaced neutral safety switch

All of my lights work except for the driver's side reverse light

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

[Dashman]

The metal lamp housing has to make ground contact. Clean the metal surfaces that make contact between the body and the housing.

[PbFut]

Use a multimeter and verify you have 12v at the socket. If you have power it's a simple ground issue at the socket or light housing. If no power, start tracing back. If the other side is lit, then you will not have far to trace. Both left and right use a common +12v wire from the switch. If other side is lit, the problem is between the intersection of the hot wire and the failed lamp. If you do not have a multimeter, spend 10 bucks at harbor freight. It will be one if the most useful 10 dollar tools you'll own.

[kwmech]

just because the bulb looks good doesn't mean it is. I've been fooled more than once

[HO455]

Originally Posted by kwmech

just because the bulb looks good doesn't mean it is. I've been fooled more than once

I'll second this one!

[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.

[slowboy]

Originally Posted by RustyPile

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.

Thanks
No voltage at the non-working socket.
Checked bulb with my digital multimeter.

[slowboy]

Originally Posted by PbFut

Use a multimeter and verify you have 12v at the socket. If you have power it's a simple ground issue at the socket or light housing. If no power, start tracing back. If the other side is lit, then you will not have far to trace. Both left and right use a common +12v wire from the switch. If other side is lit, the problem is between the intersection of the hot wire and the failed lamp. If you do not have a multimeter, spend 10 bucks at harbor freight. It will be one if the most useful 10 dollar tools you'll own.

Thanks
I checked with meter, no voltage at socket.

[RustyPile]

Originally Posted by slowboy

Thanks
No voltage at the non-working socket.
Checked bulb with my digital multimeter.

Originally Posted by slowboy

Thanks
I checked with meter, no voltage at socket.

Go back and read my post and post #3.. There is your solution...

[PbFut]

Remember, it's a one wire socket so you need ground. I would attach one lead of meter to good ground, then check the +12v pin in socket. If the socket and or housing is free from truck no risk of shorting. If housing still attached to truck careful with your probe. To verify housing is properly grounded, check ohms from socket lip to a good ground point. You should not see more than 1 to 3 ohms depending on how clean the contact surfaces are and distance between each point. Since the other side works the problem is going to be close and easy to find.