Ran test today on the 7 plug on vehicle. Shows 12v, energized all time, no key in truck etc. Its leaving my passenger side light on the trailer on all the time. Any advice? Left, right turns signal work correctly, and so does brakes when vehicle is on.


 

I would say it’s more of a trailer wiring issue then the 7 pin on the trucks side. You can isolate the problem by ruling truck out first - if you google 7 pin trailer wiring you will see the standard pattern and you can use a test light to verify each pin is working as designated. Same goes with the trailer - my guess is something on the trailer wiring side. A few minutes with a test light and continuity tester and you can easily solve it.

 

Thank you for the response, the spoiler is attached in the above, already did a test; the 12v is showing hot all the time. Just not sure if its suppose to or if something is wrong on the trailer side.

 

question is, is the 12v connector vehicle side suppose to always be hot? If so its a short on the trailer side causing the light on one side to stay on. If its not suppose to be hot something is off on the vehicle side, i cant get this affirmed.

 

My spyware? it was a picture attached using the upload here from a cell phone. Picture is just showing the test plug on the vehicle with the 12v lite up. Again is the 12v on the vehicle side suppose to always be hot? If so then this is a bad connector or grounding issue on the trailer side.

 

screenshot using lightshot, or you think its spyware to?

 

On a 7 pin trailer connector, pin #4 on truclk side IS full time unswitched 12v. This is due to the fact some trailers require continuous 12v. YOUR trailer is most likely wired incorrectly to that pin.

Check your trailer harness and correct the lights that are currently full time on to the appropriate pin you need, which is most likely pin#3. - someone may have wired trailer incorrectly on the 3/4 posts...you can see how it could easily be reversed if someone read the schematic wrong when wiring the trailer (inadvertenly inverted).

On your truck that 12v continuous is located at this fuse location- "stud 1" (if your rig is 2003-2007) I am unsure on 2008/9

 

Thank you Chrmer3, Ill attach what he had, but the wire to the right side turn signal was wired to the 12v. Inside of that was rough, so got a new plug, and used noalox. New issue I have is if the guy had the brakes wired correctly. I can see he had the blue which is the trailer brake fine, and the white to the ground. White by color code is ground typically, but Im not sure what would be correct here as the other wires where so far off. Ill attach a picture of what Im seeing under the trailer; the blue and white wire goes into a mess of wires. Question is do both the blue and white need to share the same brake connection on the plug, or do I need to leave white wire in this situation connected to ground?

this was the old wire, you can see the green wire connected to the 12v. Both green wires run to the right side brake light.

starting from the right side of pic you can see the blue, and white wire; then connecting as you go left to that mess of wires. Not sure if just by glance you can tell what is going on. I am thinking the grounding would be done to trailer not back to the plug, but Im not sure so I left the white wire disconnected for time on plug to ensure I dont cause a grounding issue or surge back into the truck.

 

Seems Ill just go with white is ground, and its tied into the frame. Would seem the brakes would be grounded back to frame as the lights are; but I havent done alot of dc wiring. Thanks for the advise, it got me on the right track; lights all work correctly, just dont know a way to verify if brakes work correctly.

 

If i we’re you, just wire the brakes fresh - least you know the trailer wire will be correct now. As I am sure you have found out, if something seems to be wired incorrectly to begin with -it’s sometimes easier just to tear it out and rewire correctly.