Do bulb sockets go bad (short out)?
 

Truck sat a while during the LS swap. Now I have all my lights except taillights and marker lights. Using the power probe on the rear section of the harness (disconnected from the main) I get a dead short on the taillight (brown) wire. I see no damage anywhere (truck is very clean). Just asking before I start cutting and replacing.

Re: Do bulb sockets go bad (short out)?
 

What is a power probe? What are the steps you followed to test?

Re: Do bulb sockets go bad (short out)?
 

trailer wiring or butchered remains hidden back there??

Re: Do bulb sockets go bad (short out)?
 

If you are reading (testing) for continuity between the brown wire and ground for a short, you must remove all the bulbs in the tailight circuit or you will read through the bulb filaments and get a small ohm reading giving you a false positive between the brown wire and ground. I don't know what the resistance of all the bulbs will be but if it is less than 50 ohms I would suspect a short.

Re: Do bulb sockets go bad (short out)?
 

I'm gonna guess brake light switch. Did you upgrade the brake light switch for the ls swap to the f body switch like most do? When i did mine i didn't wire it correctly and had a similar issue.

Re: Do bulb sockets go bad (short out)?
 

My initial description may have been lacking. I'll try to clarify.
The rear lighting harness is disconnected at the factory plug just before the rear bumper. When I apply power to the other 3 wires in the plug, the associated light comes on. However, when I apply power to the dark brown taillight wire, it trips the breaker on my power probe (when the harness was plugged in, it blew the fuse).
There is no visible damage to the harness. The trailer lighting was a factory-style plug and play setup (no spliced wires) but I removed it from the circuit to eliminate it as a possible problem.

This is a power probe. One of the most useful tools I ever bought.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1