Trailer Harness Issues
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Tuned
Joined: May 2008
Posts: 322
Likes: 3
From: Belleville IL
Trailer Harness Issues
I have a 2019 F-250. My trailer connection is up and down and it's very random. The typical scenario is I hook up nad head out; everything is fine. After and indeterminate time, my connection starts to deteriorate. I'll see tail light out warnings, first one side then the other. Then I'll get trailer disconnected warnings. Often, I'll get trailer disconnected, trailer connected, trailer disconnected warnings. I see these issues with different trailers.
Took it to the dealership and they could not find the cause nor replicate the issue.
Anyone out there have a similar issue with their rig?
Took it to the dealership and they could not find the cause nor replicate the issue.
Anyone out there have a similar issue with their rig?
5th Wheeling
Joined: May 2026
Posts: 33
Likes: 13
Might want to trace the wires from the truck seven pin to see where they connect to the harness.
I have a brand new truck and was surprised to see the seven pin connector receptacle above the tire for an add on TPMs system did not have a dust cap.
If something is added later, the connector may have been exposed to the elements weeks or years later.
You could also add an additional ground.
Ive had difficulty using a multimeter troubleshooting wiring. Sometimes the wire was held on with a single strand which ohmed out good, but couldn’t handle the load.
I have a brand new truck and was surprised to see the seven pin connector receptacle above the tire for an add on TPMs system did not have a dust cap.
If something is added later, the connector may have been exposed to the elements weeks or years later.
You could also add an additional ground.
Ive had difficulty using a multimeter troubleshooting wiring. Sometimes the wire was held on with a single strand which ohmed out good, but couldn’t handle the load.
Last edited by Ford6.7ski; Jun 12, 2026 at 03:23 PM.
7th Gear
Joined: Feb 2025
Posts: 7
Likes: 1
Did you know that there is a Ford software update to the trailer brake controllers for 2019 F250's? I was having intermittent trailer connection issues (trailer connected / disconnected dash messages when the trailer was not hooked up) and after getting the update several months ago, no more dash messages. .
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