Explorer Pass Side Trailer Stop Light NG at Harness

[seachunk2]

I've been searching for an answer why ONLY the passenger side stop light does not work on my '98 Explorer trailer harness. The passenger side signal & running lights work fine.

Everything works on the drivers side (i.e. signal, running & stop lights).

Also everything works on the vehicle on both driver & passenger side.

My Explorer was factory tow packaged. The adapter harness that connects to the factory tow light plug is fine. There just isn't any power for the passenger side stop light (green wire, right side wire).

The harness output for passenger side directional signal is fine.

 

[corkey]

it looks to me like you need to check the whole wiring harness for the trailer from 1 end to the other to see if there are any breaks in the wires or corrosion

 

[seachunk2]

I don't have the trailer hooked up to the vehicle. I'm testing from the 5 pin trailer connector on the vehicle. The trailer is brand new. That light didn't work with the old and also the new trailer, regardless if I had the trailer fully connected or not at all.
It's a problem on the vehicle side. I do not get 12V when I apply the brakes to the green wire on teh 5 pin connector. I tried back probing the wire harness and got as far as beneath the rear passenger seat. There is continuity to that point so I know the adapter harness is OK (the harness that plugs into the factory female plug located on the drivers side beneath the tail light).
I thought there might be a a relay or even a fuse problem since the passenger side directional signal works on both the car and the trailer (when I hook the trailer up), I'm not sure what it might be. I found other posts where neither the stop or signal lights worked on the passenger side but that problem was due to a faulty ground.

 

[corkey]

i bought one of these to check the light wiring ,,

that helped a ton,

 

[windsors03cobra]

That happened to mine and I just went further back and spliced it in, wire was broke somewhere. Bypassed the break and its fine.

 

[seachunk2]

Thanks. Splicing into the wire that feeds the stop light on the drivers side (yellow) is where I was heading. I stopped to ask on this board in case it turns out to be a bad component like a relay. If I had a schematic of the entire stop light passenger side circuit I could trace it out and find the fault. I guess it doesn't pay to bother. The splice should do it.