Random "Trailer Disconnected" Message
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More Turbo
Joined: Mar 2024
Posts: 535
Likes: 451
Random "Trailer Disconnected" Message
While towing I'll get the disconnect message at random times. It just flashes and dings. Brake work fine and I turn on the running lights and can't catch them going 9ff when the message pops. 7 pin is plugged in tight and has been cleaned and dielectric grease sprayed on it.
Any experience with this?
Maybe a short in the plug cable? Just started first tow after the trailer has sat in storage for a few months.
Only change is I pulled the lithium and installed a deep cycle battery since I'll be selling it soon.
Any experience with this?
Maybe a short in the plug cable? Just started first tow after the trailer has sat in storage for a few months.
Only change is I pulled the lithium and installed a deep cycle battery since I'll be selling it soon.
Last edited by Phillbo; Feb 15, 2026 at 10:20 PM.
Fleet Mechanic
Joined: Jan 2020
Posts: 1,363
Likes: 410
I had some random trailer messages, lights, and dings a few years into owning my 2020. For me, I layed on back under rear bed, unplugged every plug in on harness, sprayed with wd-40, re-assembled. Has never done it since. Next maintenance day I actually plan to do the same for good measure. My guess is water/moisture gets in plug and wicks across connections slightly.
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More Turbo
Joined: Mar 2024
Posts: 535
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Huh... I'll have to do a visual.. I live in the desert but our last trip was up into Montana and we saw a lot of rain while there.... It should be all dry by now but maybe some corrosion?
Last edited by Phillbo; Feb 16, 2026 at 01:23 PM.
Logistics Pro
Joined: Jan 2010
Posts: 4,049
Likes: 1,607
Yeah the connectors at the back of the truck seem to not be as water-tight as they should be. If cleaning them and adding some di-electric grease (better in this instance than WD40) doesn't solve the issue, then it MAY be the trailer plug. Some of them are rather cheap flat blades, and they don't maintain good contact with the truck's plug. Newer trucks are much more finicky about it than older ones.
Cargo Master
Joined: Apr 2021
Posts: 2,015
Likes: 749
From: Texas
Always check the trailer GROUND to trailer frame and via the 7 pin connector
loss of ground is 1st on list
followed by the connectors for water etc
grounds tend to be random like bumps in road etc and if trailer has an emergency break away battery that is dead or wont take a charge it will trip on and off
ONE would think this day in age
the truck could give us a message in IP other than disconnected as to at least a partial reason
loss of ground is 1st on list
followed by the connectors for water etc
grounds tend to be random like bumps in road etc and if trailer has an emergency break away battery that is dead or wont take a charge it will trip on and off
ONE would think this day in age
the truck could give us a message in IP other than disconnected as to at least a partial reason
More Turbo
Joined: Aug 2025
Posts: 646
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Mine does it every rainy day.
Engine oil dripped down the frame to the front of the trailer plug. It swelled and lets water in now. Ill seal it up with GE clear silicone next time its dry enough to roll around on the ground.
Engine oil dripped down the frame to the front of the trailer plug. It swelled and lets water in now. Ill seal it up with GE clear silicone next time its dry enough to roll around on the ground.
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Cargo Master
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Last edited by CathedralCub; Feb 25, 2026 at 10:20 PM. Reason: Changed an errant "o" to a correct "i"
Cargo Master
Joined: Mar 2007
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I would suspect a connection issue. Contrary to most opinions, dielectric grease does not improve conductivity. It's design to keep the elements out of the connector to prevent issues.
Since you have connection issues, you need to handle that first. Using contact cleaner might help with oil residue, but if the contacts are dirty [oxidized] you need to handle that first. A light sanding with 400-600 grit sand paper will help, but it's almost impossible to do that with a female side of the connector. Any place with a connection is suspect. Wires are the last thing I would suspect since they tend to be well shielded from the environment. Once corrosion seeps in, it can work down the copper wire where it causes problems that only replacing can fix.
You got a problem, it's intermittent and finding is is time consuming. Using the wrong products to fix that connections is not going to help you. Probably just get you more confused why nothing you are doing is working. Find something that removes oxidation since I believe that is the root cause of your problem.
Since you have connection issues, you need to handle that first. Using contact cleaner might help with oil residue, but if the contacts are dirty [oxidized] you need to handle that first. A light sanding with 400-600 grit sand paper will help, but it's almost impossible to do that with a female side of the connector. Any place with a connection is suspect. Wires are the last thing I would suspect since they tend to be well shielded from the environment. Once corrosion seeps in, it can work down the copper wire where it causes problems that only replacing can fix.
You got a problem, it's intermittent and finding is is time consuming. Using the wrong products to fix that connections is not going to help you. Probably just get you more confused why nothing you are doing is working. Find something that removes oxidation since I believe that is the root cause of your problem.
Logistics Pro
Joined: Jan 2010
Posts: 4,049
Likes: 1,607
I would suspect a connection issue. Contrary to most opinions, dielectric grease does not improve conductivity. It's design to keep the elements out of the connector to prevent issues.
Since you have connection issues, you need to handle that first. Using contact cleaner might help with oil residue, but if the contacts are dirty [oxidized] you need to handle that first. A light sanding with 400-600 grit sand paper will help, but it's almost impossible to do that with a female side of the connector. Any place with a connection is suspect. Wires are the last thing I would suspect since they tend to be well shielded from the environment. Once corrosion seeps in, it can work down the copper wire where it causes problems that only replacing can fix.
You got a problem, it's intermittent and finding is is time consuming. Using the wrong products to fix that connections is not going to help you. Probably just get you more confused why nothing you are doing is working. Find something that removes oxidation since I believe that is the root cause of your problem.
Since you have connection issues, you need to handle that first. Using contact cleaner might help with oil residue, but if the contacts are dirty [oxidized] you need to handle that first. A light sanding with 400-600 grit sand paper will help, but it's almost impossible to do that with a female side of the connector. Any place with a connection is suspect. Wires are the last thing I would suspect since they tend to be well shielded from the environment. Once corrosion seeps in, it can work down the copper wire where it causes problems that only replacing can fix.
You got a problem, it's intermittent and finding is is time consuming. Using the wrong products to fix that connections is not going to help you. Probably just get you more confused why nothing you are doing is working. Find something that removes oxidation since I believe that is the root cause of your problem.
On these trucks, it is relatively well-documented that a couple connections under the truck are not always as water-tight as they should be, and that pulling them apart, cleaning them, and applying some dielectric grease usually fixes the problem unless it is more serious. It is a good place to start, at least, to cover the 'common' problems, especially when they're relatively cheap/free with the exception of your time.
Cargo Master
Joined: Mar 2007
Posts: 2,757
Likes: 998
I never mentioned that anyone did, but I am certain we have both read enough threads that make people believe dielectric grease fixes everything, including electrical connections.
The issue here is an intermittent connection and terminal contacts are probably 99% of the cause.
The issue here is an intermittent connection and terminal contacts are probably 99% of the cause.
Laughing Gas
Joined: Oct 2014
Posts: 962
Likes: 114
From: Middle TN
While towing I'll get the disconnect message at random times. It just flashes and dings. Brake work fine and I turn on the running lights and can't catch them going 9ff when the message pops. 7 pin is plugged in tight and has been cleaned and dielectric grease sprayed on it.
Any experience with this?
Maybe a short in the plug cable? Just started first tow after the trailer has sat in storage for a few months.
Only change is I pulled the lithium and installed a deep cycle battery since I'll be selling it soon.
Any experience with this?
Maybe a short in the plug cable? Just started first tow after the trailer has sat in storage for a few months.
Only change is I pulled the lithium and installed a deep cycle battery since I'll be selling it soon.
I also get this message with my 2015. For some reason Ford thought it would be cool to mount the female side of the plug sideways. This puts a different strain on the cable when turning, etc, and the pin that sends power to the brakes is the first one that will lose connectivity. I ended up using a couple of zip ties to keep it tight in the socket one time while away from home.
When this issue shows up from time to time, I replace the trailer male 7-way plug and it goes away. The best I can figure, the raised tab on the male plug wears down from being pulled and reinserted, allowing it to be a little lose in the receptacle.