My back right brakelight/blinker doesn’t work.

That back corner comes on when the lights are on, and the reverse light works. Only the brake light and turn signal don’t work. The blinker in the dash does not show anything wrong. Checking with a voltmeter the inside of the receptacle I get 12 volts from the running light side and just a tiny amount of voltage from the brake/ turn signal side. Even in crimping the receptacle from the wires going into it I get 12v from the running light wire and almost nothing from the brake/turn signal wire. Every other light all around the truck works as intended

If the bulb receptacle wasn’t grounded correctly the running light wouldn’t come in when the headlights were turned on right?

If so that would mean my problem is with the power wire going to the brakelight/turn signal side of the the bulb receptacle. I’m pretty sure both back sides get power from one place and it just splits it for both sides. So that would mean that AFTER the power wire splits from left to right my right side is damaged or not supplying power.

Does this sound right to you guys? If so I’ll crawl under the truck again and trace from my back right side forward until I find where they split. There should be a main plug coming from the cab/main harness for the rear of the truck I assume? I ask because some times I’m okay with wiring, and sometimes it works the exact opposite of how I thing it would.

 

I am not sure that is correct. The brake light and turn signal come off a green wire. The taillight and side marker come off a brown wire that connect both together. It sounds like you have a problem with your green wire. Also, the bulb assembly itself is grounded separately from the side marker. It is possible to have power and a good ground to the side marker, and not have a good ground at the taillight. In short, the green wire goes straight back and connects to and only to the passenger brake light/turn signal. The brown wire comes back, splits for the license plate lights, left and right tail lights, and left and right side marker lights.

 

Its probably in the turn signal switch in the steering column. Mine was doing the same thing, and that fixed mine.

 

Are you saying that the brake light/turn signal and the running light is a separate ground for the same receptacle? Or by side marker light do you mean the lights on the left and right side? I figured the long thin side marker lights would be a different ground.

The whole brake light/ turn signal/ running light grounds off the one point correct?


Ill check the green wire out.


The switch in the column has been iffy for years. Doesn’t turn off or won’t turn on sometimes.


The green wire does the passenger brake light/turn signal and the brown wire splits for everything else on both sides?

 

Are you saying that the brake light/turn signal and the running light is a separate ground for the same receptacle? Or by side marker light do you mean the lights on the left and right side? I figured the long thin side marker lights would be a different ground.

There is a ground off the brake light/turn signal socket that attaches to the metal behind the lens. There is a separate ground for the side marker light. There is a third ground for the socket for the reverse light.

The whole brake light/ turn signal/ running light grounds off the one point correct?

No, see above. Two points usually.

Ill check the green wire out.


The switch in the column has been iffy for years. Doesn’t turn off or won’t turn on sometimes.


The green wire does the passenger brake light/turn signal and the brown wire splits for everything else on both sides?

Yes, the green wire is just for turn signal and brake light on the passenger side. Brown wire is tail lights on both sides, side marker lights on both sides, and usually license plate lights when the headlights are on.

 

Great video
He pulls the wire out of the socket and it is corroded.
Check out the video.

Advance to the 16:10 mark

 

Try pulling off both rear lenses and look at which filament lights up within the bulb with the running lights on, should be the outer one. Then try the hazards or turn signal to make sure the inner one (bright one) is blinking. Like the video i-w posted if things are not working like they should it very well could be a rusty or broken ground connection within the socket itself. $10 bucks at the parts house will get a replacement socket. I fought a similar issue with the front running/TS lights and the replacement socket was the fix. I did have to strip back a bit more wire from the stock wiring than I wanted because it was corroded black inside the wiring sheath itself to get clean wire. If you are going to crimp the new socket on be sure to load the crimp with dielectric grease or coat it all with silicone under some shrink tubing so you don't have to revisit this problem for a while.

 

I had a problem similar, mine was the back up lights. There are four wires in a bundle go back past the gas tank, left, right, tail, BU lights. Just the four in the wrap. All had current when supposed to in front of the tank over the rear axle, but BU feed was dead after the tank at the exit hole in the rear frame crossmember. I cut the plug off, leaving me some wire for splicing back. Pulled wire bundle through hole in front of tank, there is where I found teeth marks and chewed wire wrap and chewed through BU light wire (black w/red) ... I pushed wire back into the tank abyss area, pulled it into view under tank. I added wire I had added at the plug, fed it through the rear, respliced colors, wrapped each piece of shrink wrap and the bundle as one with 3M Super 33 tape and a piece of plastic 1/2" split loom long enough to exit the frame at both ends. Tucked it back up beside the tank. Hoping rodents do not like Super 33 or plastic loom. I twist and solder my splices that are staggered so no huge knots.

 

The 2-piece plastic sockets with 2-piece ground have been a problem since new. Caused many hours of head scratching and grief. Some new sockets and wire pig tails don't match up, have to check for yourself.