Tail Lights an intermittent story

[bullington]

Just moved to Pendleton Oregon, driving down Main St. The local police pull me over to tell me that my tail lights don't work. I hop out and look and they are on. I hop back in and look for the red glow reflection and they are off again.

The brake lights work, blinkers work, it is just the running lights that are intermittent.

So what is your knee jerk reaction to as the cause?

Brake Switch?
Headlight Switch?
Bad Ground?

[vectorit]

Bad ground more than likely.
My tail lights do the same thing, and I know I have grounding issues.

[CowboyTruckGreg]

also make sure u have a good body ground to the battery

[va72longhorn]

Do the rear side markers act the same?

[bntmotorcycles]

I had some with mine too. It turned out to be a connection for the rear harness located just above the instrument cluster. It's located about the center of the cluster right under the dash pad. You have to pull the cluster to get to it. All I did was clean terminals, plug in securely and black tape it together. End of problem. Just a thought!!!!

[bullington]

Thanks for all the feedback. It will give me some areas to look at.

Longhorn I will have to look at the side lights tonight and see if I can repro. Is that a ground issue if they go out too?

[va72longhorn]

If the tail lights, plate light, and rear side markers act the same, but the front markers are normal, then its either a ground between the frame and bed, the wire harness plug at the rear of the truck, or the connecter that bntmotorcycles is referring to.

If all the parking lights, back and front, act the same then its under the dash ( i.e. light switch) or under the hood at the fire wall.

The brake, turn signals, and markers use the same ground reference so I would almost rule it out and concentrate on the actual tail light circuit. If its that intermittent, then have someone watch the rear and start pulling (gently) back and forth at the factory wire harness plugs (with the lights on ....lol). Dont forget to rule out any splices due to trailer wiring, as well. Ive seen many times that someone has spliced a circuit by cutting the wire and using a wirenut and tape. No matter how hard you try, the copper wire corrodes in the splices and starts an intermittent contact in the wirenut.

Just from my experience.......

[bullington]

Thanks. So the brake lights do work when the tail lights are out so. That narrows it down a bit..

[bntmotorcycles]

One more thing mine did. When the headlamps were on the tail lights didn't work when the head lamps were on bright or dim I can't remember which. But one and not the other. Then look at that connector over the cluster.

[bullington]

Found the culprit wires. Pic is attached, the wires and connector is close to the brake pedal mechanism. It looks like it was pulling or rubbing up against the metal.

No definite smoking gun, but since rerouting it the lights have stayed on. I'm guessing I have a bare wire that needs to be protected.