only Marker rear lights not working

Its the marker lights only, everything else works on the truck and the trailer when hooked up

 

I called Freightliner Tampa just in case i do need that $16 receptacle part # 15720

 

I guess I should have a little more precise on what I meant by "socket on the truck". You'll probably need the 7 way harness for the truck, which basically is a 7 way socket with a pigtail that connects to the truck wiring through a connector.

 

Likely just the 7 way plug. Undo two bolts and unplug it from wire harness. Plug new one in and away you go. 10 min fix.

 

I’m hoping I have a lose wire in the trucks socket receptacle. Remember all my other lights work in the truck and trailer

 

Have you thought about buying a 7 way tester to narrow down the issue?

https://www.amazon.com/IPA-Tools-78...+tester&qid=1591403726&sr=8-3#customerReviews

 

And that’s why I’m saying it’s likely the plug. Stop and think about it. Marker/tail light circuits have constant power all the time while lights are on. That draws salt in. Signals/brake light circuits never ever fail as often.