Trailer brake not working

[Wild Pig]

My trailer brakes eventually quit every time I pull my camper. Sometimes they quit within the first 5 mins, sometimes after a couple of hours. The way I "fix" it in order to finish my trip is by disconnecting my battery for a minute(not very convenient) and continuing my trek. I've been to my dealer a few times but never when it's acting up. My dealer is fantastic and trying everything they can. Seems like an engineering/software issue. Hopefully Ford is on it and it gets resolved soon.

You disconnected the battery in the truck itself, correct?

I was trying to reason out if the battery on board the trailer sent any power to the brake system or are they all separate circuits fed by the truck.

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[NVanRVer]

Took the truck to the dealer today, they are ordering a new brake controller module. Should get installed sometime next week. Next trip is September 2 so we’ll see if anything changes.

 

[tderouchie]

Took the truck to the dealer today, they are ordering a new brake controller module. Should get installed sometime next week. Next trip is September 2 so we’ll see if anything changes.

unfortunately, that doesn't fix it. I tried

 

[tderouchie]

You disconnected the battery in the truck itself, correct?

I was trying to reason out if the battery on board the trailer sent any power to the brake system or are they all separate circuits fed by the truck.

Sorry. Yes I disconnect the truck battery and it resets the modules.

 

[JEB]

Sorry. Yes I disconnect the truck battery and it resets the modules.

I was having a great deal of difficulty yesterday getting the brake controller to recognize that a trailer was connected. The running, brake and turn signal lights all worked, and the active trailer selection screen popped up, but the trailer brake controller still showed no connection. In addition, my wireless back up camera on my trailer, which relies on 12v auxiliary from the truck, wouldn’t power up. What ultimately worked for me was to turn off the truck, let it power down and then unplug the 7-way. With the 7-way disconnected, I then restarted the truck and turned the headlights full on—not off or auto. I then plugged the 7-way back in. Everything came on line normally, including the brakes and the camera.

What I think is happening is that the “smart” configuration software is looking to the 12v pin to determine whether a 7-way plug is connected and, at least on my truck (and the Chevy I owned prior to my F-150), the only time the 12v pin is fully energized and providing 13.6v auxiliary power to the trailer is when the headlights are on.

I have only had an opportunity to test this procedure twice so far, so I am reluctant to call it a “fix,” but it did work after about 30 minutes of trying everything else I could think of short of disconnecting the battery.

I am now turning the headlights on before connecting and leaving them on at all times whenever I am towing.

 

[Woody]

I'm having issues with trailer braking as well. Brake module is set to a gain of 10 and I can just barely feel the trailer brakes grabbing. Took my RV which is a brand new Winnebago to the RV dealer for warrenty and they diagnosed the issue to be with the truck, not the trailer. Got an appointment next Wednesday at the Ford dealer to get this fixed. Will let you know the results of that.

 

[JEB]

I’ve confirmed it. At least for my truck. Turning the headlights off is cutting power to the 12v pin on the 7-way, which in turn is tricking the brake controller into thinking the trailer has been disconnected. Always tow with the headlights set to on, not off or auto, and the problem goes away.

For those who have been losing brake control during a journey, two things might be at work and both relate to using auto headlights. First, if you started out in low light conditions with the headlights on and then things brightened up, that could cause the headlights to go off automatically and the brake controller to disconnect. Second, the truck defaults to auto headlights after each ignition cycle. So, in bright conditions, the headlights won’t be on to begin with when you start the truck, there will be no voltage on the 12v pin and the trailer brake controller will start off disconnected.

The side benefit to making sure you always tow with the headlights on is that, if you are towing a travel trailer, having the 12v pin live will help maintain your house batteries during the journey. It’s only a trickle charge, but it’s better than nothing.

 

[chrisp993]

JEB, making sure I understand your theory - are you saying that if you start the truck, turn headlights to Off, then this will disable the Brake Controller? And that if you then turn headlights to On the Brake Controller will be restored? Or something more complicated or intermittent?

This would seem like a pretty easy test - I should get the chance later today or tomorrow!

 

[JEB]

JEB, making sure I understand your theory - are you saying that if you start the truck, turn headlights to Off, then this will disable the Brake Controller? And that if you then turn headlights to On the Brake Controller will be restored? Or something more complicated or intermittent?

This would seem like a pretty easy test - I should get the chance later today or tomorrow!

Partly. What I’m saying is that the software that configures the brake controller appears to be looking for a live 12v pin to know that a trailer is attached and that the 12v pin, from what I can tell, is live only when the headlights are on.

What you say seems to be a reasonable inference but I am reluctant to speculate that you are correct because of the glitch I discovered with my first failure where the software appeared to assign brake function to the headlights. I think it would be very dangerous, for example, to be cruising down the road, notice that your brakes weren’t working, and then try to restore function by turning on the headlamps. That could cause a brake lock-up if the glitch I discovered reappeared. Thus, all I can verify is that if you connect the trailer while your headlamps are already on and before you are underway, the brake controller configures properly, and reliably, and will remain connected for at least that ignition cycle. But you have to do this before you start moving to be safe.

That said, your theory could be safely tested if you were stopped. Why not try it? It is entirely possible that the reason my brakes locked up when I turned on the headlamps is because I was only creeping along at the time with my foot mostly on the brake, which would have caused the brakes to engage. So, it really wasn’t the headlights per se that engaged the brakes directly but rather the headlights that turned on the brake controller which then saw my foot on the brakes and immediately activated.

 

[justinwvu]

This is good empirical data based on the behavior of the brakes and it does appear that you lost them at some point. But what I was really hoping to see is if anyone manually activated the brake controller before setting out, verified from the gain pop up (not the ”trailer connected” pop up) that the controller showed an active connection, and then subsequently lost the connection while driving. I haven’t seen that specific scenario yet. In my experience, there were a few times when I thought the trailer brakes were working based on how the truck was stopping only to learn that they actually weren’t connected at all—I just thought they were. I haven’t experienced a disconnect while driving after verifying on the gain screen that the trailer was connected.

Jeb, on the two examples I gave on my previous post, I did indeed do a manual override before setting off on my trip and verified the brakes were working. I always do this now since I have had this issue and I had assumed that if they were working when I left I was good. I was quite surprised when they had stopped working mid trip.

On the first trip I had stopped briefly at a rest stop and then continued the trip and did not recheck at that time admittedly. However the truck was on the whole time as we were sitting in it - which is why I didn’t recheck.

The second time it happened there was no stop other than to get gas - which again you power off to fill up. Plus I did reconfirm they were working with the manual override before leaving the gas station. Brakes stopped working again on the way to Lincoln sometime during this last leg of the trip.

 

[justinwvu]

Jeb, I think your theories are on the right track, I will do some testing next time I tow.

I think that when I stopped at Walmart and got the compressed air what really worked was the fact that my truck was off for 10 or 15 minutes and then I turned it back on and reconnected. I can’t remember for sure but I think I connected the trailer before I turned the truck on that time. I typically had been turning the truck on first and then connecting trailer

I'm not sure about the headlight issue, I tow with them on because it’s the only way my rear view camera on the back of my airstream works so I don’t think that’s been getting cycled off or to Auto. I’ll watch for this though.

I had my truck at the dealership this week, they tested the trailer brake and told me everything checked out on their end for what it’s worth.

(I made some edits, dictating on iPhone had all sorts of errors)

 

[wmwalker]

Today, we started shopping for a new truck.

Yesterday, the orange "Trailer Disconnected" popped up while descending a 6% grade with an 8500lb load. Interestingly, squeezing the manual brake did show it working on screen — but it was all a lie. We used the transmission to help slow the vehicle for the remainder of the descent. When it was over, our brakes were smoking.

This is the third time we've experienced such an event.

Ford, if you pay attention to this thread you should say something before the lawyers do.

 

[chrisp993]

Partly. What I’m saying is that the software that configures the brake controller appears to be looking for a live 12v pin to know that a trailer is attached and that the 12v pin, from what I can tell, is live only when the headlights are on.

What you say seems to be a reasonable inference but I am reluctant to speculate that you are correct because of the glitch I discovered with my first failure where the software appeared to assign brake function to the headlights. I think it would be very dangerous, for example, to be cruising down the road, notice that your brakes weren’t working, and then try to restore function by turning on the headlamps. That could cause a brake lock-up if the glitch I discovered reappeared. Thus, all I can verify is that if you connect the trailer while your headlamps are already on and before you are underway, the brake controller configures properly, and reliably, and will remain connected for at least that ignition cycle. But you have to do this before you start moving to be safe.

That said, your theory could be safely tested if you were stopped. Why not try it? It is entirely possible that the reason my brakes locked up when I turned on the headlamps is because I was only creeping along at the time with my foot mostly on the brake, which would have caused the brakes to engage. So, it really wasn’t the headlights per se that engaged the brakes directly but rather the headlights that turned on the brake controller which then saw my foot on the brakes and immediately activated.

OK, picked up my trailer - started with headlights OFF, plugged in trailer and, trailer brake tested OK, drove away and tried switching headlights from OFF to ON to AUTO, made no difference, trailer brakes worked fine under all cases. I'm not saying there isn't something going on with the software / electrical configuration, but it isn't as simple as headlights ON = brakes working. Additionally, when I've had the trailer brakes stop working during a journey, its been with headlights on AUTO but during the afternoon on open road, so nothing related to headlights would have switched ON or OFF to cause the malfunction. I'm still stumped ...

Ford, if you pay attention to this thread you should say something before the lawyers do.

Yup, I'm really surprised this issue exists, let alone seems relatively widespread ...

 

[Ed21]

OK, picked up my trailer - started with headlights OFF, plugged in trailer and, trailer brake tested OK, drove away and tried switching headlights from OFF to ON to AUTO, made no difference, trailer brakes worked fine under all cases. I'm not saying there isn't something going on with the software / electrical configuration, but it isn't as simple as headlights ON = brakes working. Additionally, when I've had the trailer brakes stop working during a journey, its been with headlights on AUTO but during the afternoon on open road, so nothing related to headlights would have switched ON or OFF to cause the malfunction. I'm still stumped ...

Same here, Only had the trailer out twice so far. Shouldn't have to result to all these tactics to tow a trailer.

Yup, I'm really surprised this issue exists, let alone seems relatively widespread ...

Yes indeed. If it happens on my next outing I will probably proceed to file a complaint with the NTSB. This could have devastating consequences!

 

[justinwvu]

Today, we started shopping for a new truck.

Yesterday, the orange "Trailer Disconnected" popped up while descending a 6% grade with an 8500lb load. Interestingly, squeezing the manual brake did show it working on screen — but it was all a lie. We used the transmission to help slow the vehicle for the remainder of the descent. When it was over, our brakes were smoking.

This is the third time we've experienced such an event.

Ford, if you pay attention to this thread you should say something before the lawyers do.

Yikes,

Sad thing is I otherwise love my truck. I'm going on a trip September 9-12, if it happens again I may have to start searching as well.

It's also really hard to buy a new truck right now....

Glad you're OK.

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