Was wondering if there is a common point on our trucks where the wires rubs and becomes an open.

My right rear brakelight/turn signal is not working. I checked the bulb and the fuse and both are fine. The socket for the bulb is corroded though. The next thing I'm going to try is extra dialectric grease and hope for the best.

I thought about replacing the harness as well.

 

Stick a GROUNDED test-light to the contacts inside the bulb-housing; one should light when the tail-lights are ON; the other should light when the right turn is ON.

Be sure to not let the test-light probe touch the housing and contact at the same time, as it will shoot the fuse.

Also, TEST the bulb, even if it looks good.

A little wire-brush in a Dremel-type tool will shine the contacts and also the inside surface of the housing.

I figure your problem is either dirty contacts or a dirty GROUND.

Unless, someone has used one of those silly "suitcase" quik-splice gizmos and thus cut the wire to where it has finally broke; doubtful, though, since you say you have lost both sides of the bulb; that leads me to figure GROUND, as it is the only thing shared in common between the two functions.


On edit:

I re-read your post and you didn't mention whether or not the tail-light worked.

If the tail-light portion indeed works, then it could very well be one of those quik-splices.

A quick easy way to trouble-shoot would be to alligator-clip a test-wire to a good GROUND, then probe the other end of the wire to the bulb-housing, thus GROUNDing it; if the bulb then works, you know the problem is the GROUND.

 

Yeah when the headlights are on, the taillight lights up, thats the single filament bulb I think. The double filament bulb, which is brakes/turn signals in not working right now. I had em backwards tonight, so it looked like my right side tailight was in reverse all the time. Fortunately I didn't see the law running around.

I guess I could also try disconnecting the harness and reconnecting it just for the hell of it.

 

Single filament bulb = 1156 = REVERSE LIGHT

Double filament bulb = 1157 = one leg is TAIL, the other is BRAKE/SIGNAL

 

1156 is not working. 1157 is.

 

Where can one get a replacement harness for the taillight?

 

went through the same thing 3 weeks ago. Baffled that good bulbs were not working(in my case, right rear turn signal). Check your front turn signal bulb, the one underneath the headlight, or the sidemarker signal. If one of those are out, as in my case, the rear won't work. Head scratching, but thank goodness cheap and easy fix.

 

alright, I will give it a shot. Thanks for the tip!

 

I'm starting to get dizzy...
Here's what my Dad taught me when I was a kid:
As bigragu said, verify that the other lights are working. Then you can just swap bulbs on the left and right sides.
If the problem moves to the other side, ya got a bad bulb. If it doesn't, there's a wiring or socket problem.
This works for your reverse, brake, signal, and side marker lights...
All you need is a screwdriver (or Torx bit nowadays).

 

Sorry for contradicting myself.

The reverse light works fine.

There is a red light on when headlights or parking lights are on.

No light turns on when turn signal or brake pedal is engaged (No double bright red).

This leads me to believe one part of the 1157 bulb is not operational. The first thing I did was to replace it but got no joy, which leads me to believe it's a harness problem.... or it could be what big ragu said. I have to check it still.