All the lights on my truck work perfectly, except the passenger side rear. The running light works when I turn on the headlights. The hazard, signal, and break does not. I replaced all the bulbs. Checked all the fuses. I took off the entire harness that runs from side to side and seen no bad spits or rubbing, they all looked ok. Any suggestions on what to do next would be appreciated.

 

The next place to look is the steering column. There are 3 different things going on in the steering column, because as you said, that light has 3 jobs it has to do.

When the turnsignal switch (called the multi-function switch in your truck) is in the center, there is a wire that comes up from the brake switch on the brake pedal that has power when you press the pedal. This wire goes up through the turnsignal switch, and since it's in the center, it puts this brake signal on both rear lights(the brighter filament in the bulbs).

There is another hot wire that comes into the switch from the turnsignal flasher(of course this is a flashing hot wire). When you move the turnsignal switch in either direction, it takes the brake power wire off that side, and puts the flashing signal power wire on the proper bulb.

Then of course you have the hazards, they are another flashing power source, but when the hazard switch is activated, it pulls all the lights front and rear off their normal duties and puts them on the hazard flasher so they all blink.

What I would do is find the wiring coming out of the column, most easiest is probably down near the bottom of the dash.

Put the signal switch in the middle, and then for verification that you are on the right track, put your testlight on the lightgreen, and then press the brake pedal. You should have power on the lightgreen going up the column when the brake pedal is pressed.

Then find the lightgreen/orange wire and the orange/lightblue. These are the two wires going to the rear lights. The orange/lightblue goes to the pass side rear. Poke this wire with the testlight, and with the lever in the middle you should get power when you press the brake pedal. If you don't, you know your problem is in the steering column, most likely the multi-function switch.