LED Park/Running Lights on trailer not working - Screen Errors

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cboshdave

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Just got a 2023 Yukon 3.0L Duramax. I have pulled my enclosed trailer with a 7 pin trailer connector several times and the lights have been fine. The last time I pulled, I got dash errors saying no trailer connected as well as parking light test error. All other lights were fine (brake, R turn, L turn). I checked fuse #41 and it's fine. I also tested the yukon with another trailer and everything lit fine, as well as the reverse. I hooked his truck to my trailer and my trailer lit fine. It's the combination of the yukon and my trailer. The trailer is fairly new as well and I'm wondering if the LED lights on it are not providing enough draw for the yukon to recognize they are on? I have seen the load resistors inline to stop the trailer turn signal "hyper" flashing. I'm wondering if I should install the same load resistor for my parking lights on the trailer? The LED turn signals seem to be the bigger problems that people have seen. I can't find anything on the park lights.

I'm also a little frustrated that we can't really "test" the 7 pin connector normally because the computer is trying to be too fancy? If there is no trailer detected, it doesn't seem to send the power to the 7 pin connector. Am I misunderstanding something here? I've seen 7 pin testers on amazon and reviews say if you have a newer GMC rig, it won't work.
 

BacDoc

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Most trailer light issues are ground problems.
Since your trailer worked on another vehicle it might be the connection on your truck, maybe a little corroded or loose connection?
 
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cboshdave

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Most trailer light issues are ground problems.
Since your trailer worked on another vehicle it might be the connection on your truck, maybe a little corroded or loose connection.

As I mentioned, my truck worked on another trailer and his truck worked with my trailer. So, I think it's specifically a problem between my truck and my trailer. I have ruled out everything else (theoretically).
 

BacDoc

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As I mentioned, my truck worked on another trailer and his truck worked with my trailer. So, I think it's specifically a problem between my truck and my trailer. I have ruled out everything else (theoretically).
I didn’t see that your truck worked on another trailer! That really makes it tough to diagnose.
Still think it’s a ground issue though.

I trailer a lot and if I have a year where everything is working with the lights then that is a good year!
Seems like trailer lights have a limited life especially when dunked in salt water and trailer is stored outside.
 

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