False wiring fault/ trailer disconnected - brakes locked up

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ynpmoose

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A weird integrated brake controller issue yesterday after towing over 800 miles across two days, several stops, including a campground where I completely disconnected. We made a fuel/bathroom stop, engine off, gassed up, started up and pulled around the side to free up the pump. Shut off and did our business. Started back up, got trailer wiring fault and trailer disconnected messages. Plugged and unplugged the trailer, still getting messages. Tried to drive forward, trailer brakes are full on, but should not be, can't move the rig. Checked lots of wiring, metered the truck plug and electric brakes are full power, when they should not be. This tells me it's a truck problem and not a trailer problem. I ended up pulling the tow controller fuses in the engine box and put them back in. Voila, everything is fine. Next two drives without a trailer, both times it complains about trailer wiring fault, even though nothing is in the plug.

What gives? Do I need to replace the controller? I'm not trusting it at this point.
 

99WhiteC5Coupe

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A weird integrated brake controller issue yesterday after towing over 800 miles across two days, several stops, including a campground where I completely disconnected. We made a fuel/bathroom stop, engine off, gassed up, started up and pulled around the side to free up the pump. Shut off and did our business. Started back up, got trailer wiring fault and trailer disconnected messages. Plugged and unplugged the trailer, still getting messages. Tried to drive forward, trailer brakes are full on, but should not be, can't move the rig. Checked lots of wiring, metered the truck plug and electric brakes are full power, when they should not be. This tells me it's a truck problem and not a trailer problem. I ended up pulling the tow controller fuses in the engine box and put them back in. Voila, everything is fine. Next two drives without a trailer, both times it complains about trailer wiring fault, even though nothing is in the plug.

What gives? Do I need to replace the controller? I'm not trusting it at this point.


You did not list your year, make, model, and what type of towing package you have.

I bought a new 2015 Ford Expedition Limited 4x4 with the HD towing package. Never damaged or wrecked.

I have never towed or even opened the four or seven pin connector covers.

Since new, the vehicle intermittently and randomly displays a “trailer wiring fault” on the DIC.

The vehicle was returned to the dealer several times and I was told since there were no codes set, there was no problem for repair. The dealer would not trouble-shoot the issue.

If you have a 2015 or later Expedition, I would chalk it up to poor Ford quality.

There have been several posts on this forum regarding the message with the 2015 - 2017 models.
 

99WhiteC5Coupe

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Maybe my signature didn't appear for you. This is a 2016 EL XLT 4x4 w/ HD tow.


I suspected you had a 2015 - 2017 model.

Your information didn’t appear in your signature, even when I am logged-in.

I don’t have an answer for you, as I still get the warnings (with no pattern). My dealer was zero help in fixing the defect.

Good luck - let us know if you figure it out.
 
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ynpmoose

ynpmoose

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Update: the brakes locked up again. Trailer Brake Module Fault. Pulling fuses to reset didn't work this time. Had to pull the fuse for the trailer brakes just so I could move, but without brakes. 10 hours from home, too far to tow this way all the way home. Called multiple surrounding Ford dealers, nobody stocks the brake controllers.

Camping World was nearby and stocked the Ford to Tekonsha harness. Picked that up and a Tekonsha P3 controller. Pulled the center dash in their parking lot and removed the harness from the factory controller. The controller was HOT!!!!. Too hot to hold onto and smelled like burning electronics. Hooked up the Tekonsha and it works great. Plug and play.

The dash still warns about controller fault, but I think I can use Forscan to tell the truck it's not installed so that will stop.

I do have an electronics degree, so I'm planning an autopsy on the failed controller when I get back. I'll post my findings and see if it is repairable.
 
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ynpmoose

ynpmoose

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Everything inside this controller is basically surface mount, low amperage chips, with no heat sinking at all. It doesn't make any sense to me when you compare this to the thickness of the wires in the harness. One of the surface mounted output ICs was popped and has no markings, so not repairable. It, and one other, had melted the conformal coating off of them. This thing either needs beefer circuitry or heat-sinks. I'm going to stick with the Tekonsha.
 

99WhiteC5Coupe

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Everything inside this controller is basically surface mount, low amperage chips, with no heat sinking at all. It doesn't make any sense to me when you compare this to the thickness of the wires in the harness. One of the surface mounted output ICs was popped and has no markings, so not repairable. It, and one other, had melted the conformal coating off of them. This thing either needs beefer circuitry or heat-sinks. I'm going to stick with the Tekonsha.


Thanks for the update.

I have found it odd that my 2015 Expedition with HD towing has repeatedly display the warning since new - and I have never connected a harness to the 4 or 7 pin connectors (and the connectors and wiring are not damaged).

I suspect the brake controller is of a poor design and the Ford dealers do not know how to trouble-shoot the problem.

With Ford’s marketing about “Built Ford Tough” - you would think the optional HD towing packages would be bullet-proof.

Good luck.
 
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