Incredibly weak tail-light problem

I've got an intermittently functioning tail, that comes on and off sporadicly, and has for years on my '96. Not flickering, just works perfectly for several months and out of the blue, not for a while. Currently NOT working as pointed out by a Sherriff's deputy recently. When I pull open both sides, both bulbs work perfectly on the other side. When I probe the bad side I'm getting 12v to the contact in the socket and there is no corrosion, and the spring seat seams fine.

Any clue as to what would cause this nonsense?

 

Have you tried wiggling the socket where you are getting power from the battery to see if you get a voltage drop? Could be an exposed/damaged wire in the circuit, or a bad contact where the wiring meets the socket.

 

You talking about the 96 or 2010?

 

96
Got ready to crawl underneath and futz with wiring some more and now all of the sudden it works. So I go to put bulb in other side and its not working but I can get it to work intermittently by pushing in on housing.??????????????????
I'm just gonna pick up 2 bulbs (1157) tomorrow and see what happens.

 

The wiring in rear looks less than pristine from trailer plug install years ago. I've owned this truck since 1999

 

If its working when putting pressure on the housing, it's not the bulb. I guarantee there's a loose solder connection where the wiring meets the socket. I'd check to see with your meter if you get continuity from the back of the housing to the front of the housing and give it a wiggle. Test on each wire to find your culprit.

Edit: Back of the socket/connector to front of socket/connector

 

If u scotch locked a trailer kit that definitely can be an issue.
12 volts means nothing like fish said.
A single strand of wire will get you 12 volts but no amps to push it. Causing high resistance.
If I have a trailer converter also I would be disconnecting the system to eliminate that part of it and do a real good visual. If you can't find anything in the back, work your way forward.
Really check those sockets like fish suggested.

 

Does that mean you spliced into the factory harness? If you did and moisture infiltrated the factory harness, guaranteed corrosion and the wires for several millimeters in each direction are going to have a green tinge to them. I'd start there.

 

^^ If this is the case, snip off those exposed ends and solder them up nicely... With shrink tubing ofcourse

 

Ya previous owner had scotch connectors done, so many potential weak spots. I'm gonna go ahead and pick up a bulb and see what happens and then continue to dig deeper as needed. I spent a good bit of time on the creeper tonight looking for obvious issues.

Thanks for all the help guys. Greatly appreciated.

 

And some dielectric grease

 

good point