[DoubleVision]

Okay. I find the rear tail light harness on my truck has been hacked up by a previous owner, so today I go to the junkyard and find one in perfect shape from a 95 Chevy truck. I installed it, reconnected it, check the tail light terminals for power, great, 12 volts. Plug in 1 tail light, nothing. Check the circuit, dead zero. Check the other side, dead zero. Call my nephew at the parts store, he brings me 2 new tail light assemblies plus bulbs, plug them in, same thing, circuit goes dead. The first thing that comes to mind is bad ground. The ground is ran direct to frame with a self tapping bolt.
Checked the tail light assembly without bulb, gets 12 volts just fine, install the bulb the circuit goes dead again. What in the bloody he** is the matter with this dam*ed thing? All the other lights work, plus turn signals, but once again, no brake lights. I`m tired of fooling with this thing and it`s the first time I ever seen lights just simply refuse to work. What gives?

[cobalt327]

I'd still suspect the ground. Try hooking a jumper to the ground to a real good, clean piece of metal. The emergency flashers aren't on, right?

If the bulbs are correct for the socket, and aren't 180 degrees out if an 1157, and there's current, all it can be is insufficient amperage, I would think. That should be a bad ground.

The fuses are good? Sometimes there can be a bleed-over of a tiny bit of current that will make a meter register, but w/o any real amperage.

[dinger]

Did the brake lights work before you replaced the wiring? You may also want to check the switch, located at the pedal. And as cobalt says, make sure the bulb is installed properly.

[gizmo-1948]

Try this--Jump the brake switch wires together, Key on, turn on left or right blinker, if one side blinks OK and the other side has brake light on, you have a faulty turn signal switch, or the wiring in the steering column to the turn switch has been damaged. You mentioned that all the other lights worked including blinkers, just no brake lights--If your blinkers work properly, that tells you that your power, ground and bulbs are good.

[T-bucket23]

If you have 12 volts and it goes away when you plug into it,you most likely have a bad connection somewhere that cant pass enough current to light the bulb. When you are checking for the 12 volts where is the meter ground or test light ground connected. If it is anywhere but the battery negative terminal you are wasting your time. One thing you could try is unplug the harness and find the wire that feeds the brake lights. Run a fused jumper from a known good 12volt source to the wire in the plug and see if the bulb lights. If it does you know both your harness and your ground are ok and the problem is up front somewhere. If the above test passes I would look hard at the brake ligh switc and its connections and the turn signal switch.
You need to eliminate stuff one piece at a time or you will just keep going around in circles.
When troubleshooting these types of problems ALWAYS use the battery neg as a ground. This will save you lots of false no power indications.

[T-bucket23]

Originally Posted by gizmo-1948

Try this--Jump the brake switch wires together, Key on, turn on left or right blinker, if one side blinks OK and the other side has brake light on, you have a faulty turn signal switch, or the wiring in the steering column to the turn switch has been damaged. You mentioned that all the other lights worked including blinkers, just no brake lights--If your blinkers work properly, that tells you that your power, ground and bulbs are good.

This sounds like how it SHOULD work

[T-bucket23]

Did you ever resolve this ?