Trailer brake module fault

[duncanmaio]

I had similar intermittent issues shortly after taking delivery (and towing a light trailer). Eventually the trailer wiring quit completely. I reached up behind the trailer connection on the rear bumper and fully seated the multi-pin connector, and everything has been fine ever since. Turns out the onboard computers like to have all the wiring plugged in all the way.

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[azzano00]

I had this same warning come up on my ''23 lightning. On others advice I sprayed the hell out of the 4 pin trailer light plug with WD-40 and so far.... not more warning.

 

[climateguy]

Just following up. Dealer wanted to keep my truck for a week to diagnose so I went ahead and pulled the under-hood fuse 42, waited a few minutes, reinstalled and the fault message and rapid blinking went away. Obviously not a root cause fix, but got my trailer lights and other related functionality working again. I will pursue a more permanent fix if the problem recurs.

I have a 2024 Flash. This vehicle has exhibited the "trailer brake module fault" warning on every start since it was new a month or so ago. The turn signal sound was very rapid as well. I didn't worry about the warning, as I assumed I just needed to set up a trailer with the controller and it would go away. I thought the rapid turn signal was just the way the Lightnings were. Duh.

Today, I plugged my trailer into this vehicle for the first time, and none of the trailer lights would work. Now, in addition to the rapid turn signal blinking and the trailer brake module fault warning, there was a warning that the Blind Spot assist is disabled.

The manual stated that a Blind Spot assist warning could mean that communication was not happening with the trailer brake module.

Since I was experiencing a trailer brake module fault warning and a blind spot assist warning, I assumed I would be heading to see the dealer. I did not like this thought.

I pulled all the fuses that had anything to do with trailers, i.e. 21, 42, 55, 56, 58, 91, and 107, made sure they were good, and put them back in. I then replaced the trailer connector that plugged into the receptacle on the bumper of this vehicle with a new one as well.

(The old one had contacts that had an aged patina, and they were spread apart compared to the new one. There was hardly any force required to plug this connector in compared to a new one. I suspected that some of the 7 points of connection from the trailer to the vehicle would have been higher resistance than normal, and some were possibly intermittent or non-existent.)

I plugged in the trailer with the new connector and the reseated fuses. When I restarted the Flash, the warnings had disappeared, and the trailer lights were working. Ta Da!

 

[Gimme_my_MME]

I have a 2024 Flash. This vehicle has exhibited the "trailer brake module fault" warning on every start since it was new a month or so ago. The turn signal sound was very rapid as well. I didn't worry about the warning, as I assumed I just needed to set up a trailer with the controller and it would go away. I thought the rapid turn signal was just the way the Lightnings were. Duh.

Today, I plugged my trailer into this vehicle for the first time, and none of the trailer lights would work. Now, in addition to the rapid turn signal blinking and the trailer brake module fault warning, there was a warning that the Blind Spot assist is disabled.

The manual stated that a Blind Spot assist warning could mean that communication was not happening with the trailer brake module.

Since I was experiencing a trailer brake module fault warning and a blind spot assist warning, I assumed I would be heading to see the dealer. I did not like this thought.

I pulled all the fuses that had anything to do with trailers, i.e. 21, 42, 55, 56, 58, 91, and 107, made sure they were good, and put them back in. I then replaced the trailer connector that plugged into the receptacle on the bumper of this vehicle with a new one as well.

(The old one had contacts that had an aged patina, and they were spread apart compared to the new one. There was hardly any force required to plug this connector in compared to a new one. I suspected that some of the 7 points of connection from the trailer to the vehicle would have been higher resistance than normal, and some were possibly intermittent or non-existent.)

I plugged in the trailer with the new connector and the reseated fuses. When I restarted the Flash, the warnings had disappeared, and the trailer lights were working. Ta Da!

A 12v reset does the trick

 

[climateguy]

A 12v reset does the trick

How do you do that?

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