2021 F150 trailer brake / brake controller nightmare

[mlmarcum]

I have a 2021 F150 XLT 3.5L GTDI V6 (VIN 1FTFW1E8XMKE08562). It's a 4x4 Supercrew with a 3.55 axle ratio and 145.5" WB. Build date says 06/21. It has the regular trailer tow package, not max tow, and it came with a factory trailer brake preinstalled. I bought it used a few months ago and it still has the factory warranty (really low mileage).

Last month I bought a brand new travel trailer (a 2023 Forest River Ibex 20MDS) and I live and travel on it fulltime (I work remote). Trailer brakes worked and threw no error codes when we hooked up at the RV dealer, but 5 minutes down the road I started getting "trailer wiring fault"... Over the next couple of days the issue went from intermittent to consistent no matter what, and now the fun begins.

What happens now:

• Now, 100% of the time as soon as I plug in, my truck throws a "trailer wiring fault" error.
• When I slide the trailer brakes, I get a "trailer disconnected" error, but all lights / turn signals are functioning as normal. Zero trailer brake output shown on screen for both slider braking and pedal braking, regardless of the gain setting.
• Bizarrely, after about 15 minutes of driving, somehow my slider brakes come online and I can use them without the "trailer disconnected" error. They show brake output on the screen and work as intended, but I see zero brake output when I use the brake pedal. This happens even when the gain is set at 10. I don't trust it and haven't driven it for more than about 30 minutes this way.

What I've tried:

• Had dealership update all software to current version - apparently my truck hadn't receieved any updates in well over a year. It took 2 full days and Sync / the menus / everything looks wildly different. Fixed a few little bugs I had but not this.
• Deleted my trailer and readded it again - nada.
• Cleaned 7-pin connector and receiver extremely well - nada.
• Added an extra ground wire from the trailer to the truck - nada.
• This suggested fix involving a load equalizer to trick the truck into seeing consistent current. We didn't want to cut into my trailer or truck and potentially void any warranty on either, so we bought an extra 7-pin and receiver, spliced the equalizer into that, and plugged it between the trailer and truck like an extension cord - nada.
• Checked trailer brake controller fuse. Looks fine, truck throws an error saying something about brakes (can't remember exact wording) when it's pulled, clears when it's back.
• Disconnected battery, let it sit, and tried again - nada.
• Every possible order of doing things - plugging in before starting truck, after, etc, nothing makes a difference.

Some considerations:

• Had trailer wiring inspected by a third party shop - they said it's perfect and the issue is on Ford. They knew of a guy going through a similar ordeal but no solution.
• Plugged a 2016 F250 - also with factory brake controller - into trailer, did not actually tow. Immediately got "trailer wiring fault" and when we tested the slide brake, "trailer disconnected".
• Plugged a very new GMC dually (don't know exact year or model, sorry) into trailer - actually towed it - zero error codes, brakes worked perfectly, no issue at all.
• Took both my Ford and the '16 F250 to my buddy's fifth wheel, plugged into it, no error codes on either. I don't have a fifth wheel hitch to truly test towing, but I could hear the brakes pulsing every ~4-5 seconds.
• I know about recall 22S17, but my truck isn't showing that it needs a fix when I check the vin. Some kind soul in another thread confirmed my trailer brake software is on the most recent version.

It's at the shop now and Ford is giving me hell over it - they have no problems on their trailer simulator and they're pointing the finger at my trailer, saying they've never heard of any issues with trailer brakes (clearly not true from this forum).

Any ideas at all? I spent so much on a high quality truck and a brand new trailer so that I can travel and live on it fulltime, and I've been stuck in Oklahoma for weeks longer than planned. I don't have a house or apartment I can just fall back to - I gotta get this fixed!

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[mlmarcum]

Update: The dealer just called me and said they're running more tests, but that my truck might just be "incompatible" with my brand new trailer. Seems like absolute BS to me - the most popular truck in the country is incompatible with a brand new travel trailer? - I'm keeping on them. All suggestions welcome for how to handle.

 

[travisN000]

I had to tighten the contacts in my trailer plug and truck receptical to get rid of the errors... software didn't fix it for me.

I also have a ram 1500 that had no issues with the trailer, but I noted that the connector was not nearly as tight on my f150. I used a pick to widen the pins on the truck's connector and narrow / approximate the contacts on the trailers plug and this helped quite a bit. I also cleaned and added dielectric grease to the contacts at the same time. I have still gotten the errors since doing this, but it is pretty rare now. My opinion is that the receptacle on the f150 is just a bit too loose / big for some trailers, but tightening the contacts seems to have improved the situation a fair amount.

 

[Cobraman428]

My Job2 2021 built date Nov 2021 works fine with my New 2023 Forest River E-PRO 20FBS trailer.

 

[mlmarcum]

I had to tighten the contacts in my trailer plug and truck receptical to get rid of the errors... software didn't fix it for me.

I also have a ram 1500 that had no issues with the trailer, but I noted that the connector was not nearly as tight on my f150. I used a pick to widen the pins on the truck's connector and narrow / approximate the contacts on the trailers plug and this helped quite a bit. I also cleaned and added dielectric grease to the contacts at the same time. I have still gotten the errors since doing this, but it is pretty rare now. My opinion is that the receptacle on the f150 is just a bit too loose / big for some trailers, but tightening the contacts seems to have improved the situation a fair amount.

I've tried tightening the contacts on the trailer's end, but not widening them on the truck's receptacle. Worth a shot, thank you.

 

[Henfield]

Thanks for linking your prior thread to this one.

Just wondering. Any signs that the PO towed? I'm wondering if the plug on the truck was damaged, is corroded or similar.

Its certainly interesting that the dealer reported the truck had not received any updates. That's a real red flag that the problems with your truck are deeper than trailer wiring.

 

[mlmarcum]

Thanks for linking your prior thread to this one.

Just wondering. Any signs that the PO towed? I'm wondering if the plug on the truck was damaged, is corroded or similar.

Its certainly interesting that the dealer reported the truck had not received any updates. That's a real red flag that the problems with your truck are deeper than trailer wiring.

Not any significant signs, but I gotta assume that if they took the trouble to upgrade an XLT with the towing package, pro trailer backup assist, etc, they probably were pulling something. I bought the truck at less than 15k miles so had to be pretty light use. I'm now at 18k so still under warranty.

And yeah, I'm with you, the lack of OTA updates is a major red flag - was hoping that the dealership forcing all the upgrades would fix this too. I don't think my truck has received any OTA since that fix, but it's only been a couple of weeks, there might not be anything available.

 

[DW2020]

In my case, the trailer end of the plug was the kind with the two blades for each pin. It never really felt like it was fully seated and had the sporadic 'no trailer' issues. (example https://www.amazon.ca/Leisure-Cords...locphy=9001316&hvtargid=pla-568664400686&th=1)

I changed the trailer end to the proper SAE spec one with single blades (like this https://www.reese-hitches.com/products/7_Way_Flat_Pin_Nylon_Trailer_End_Plug,12-706). It fit much more firmly and resolved my issue.

My personal suggestion would be to try changing the trailer side plug before messing with the truck connector. Even just try the new trailer plug without wiring just to feel the difference.

 

[Henfield]

Not any significant signs, but I gotta assume that if they took the trouble to upgrade an XLT with the towing package, pro trailer backup assist, etc, they probably were pulling something. I bought the truck at less than 15k miles so had to be pretty light use. I'm now at 18k so still under warranty.

And yeah, I'm with you, the lack of OTA updates is a major red flag - was hoping that the dealership forcing all the upgrades would fix this too. I don't think my truck has received any OTA since that fix, but it's only been a couple of weeks, there might not be anything available.

Ford links many packages together. Want this one? You have to get this one to...... Which probably explains the combo you got.

 

[JEB]

@mlmarcum . As we discussed, your TRM software is up to date. I doubt that software is your problem. Other out of date software on your truck is certainly not good, but I don’t think that that is the cause of this issue. My brake controller performance was very dicey early last year but has been perfect since May when I updated the TRM software. You have the same software I do and it is the software called for in the recall.

@DW2020 makes a good point about the type of contacts in the 7-way on the trailer side. It would explain why the performance is inconsistent. Consider buying a 7-way tester for the truck. It also has the standard SAE contacts and can help rule out issues on the truck side. https://www.amazon.com/CURT-58270-V...d=1677697113&sprefix=7-way+tes,aps,111&sr=8-5. If you can activate the brake controller consistently with the tester, and you’ve ruled out wiring issues on the trailer side with a third-party inspection, it adds some weight to the theory that it might be a problem with the way the 7-way on your trailer plays with the 7-way on your truck.

If you are really pressed and need a temporary solution just to get you out of Dodge, consider this product from Curt. It is a bluetooth wireless brake controller and requires no installation. It isn’t perfect and you shouldn’t have to deal with this, but it should get you to your next destination safely. https://www.amazon.com/CURT-51180-C...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

[mlmarcum]

Hi all, unfortunately the nightmare continues.

A Ford dealership found issues with my trailer wiring harness and replaced it. This seemed to solve the trailer wiring fault / trailer disconnected errors, but I still did not see any brake output bars displayed when using the pedal brake, regardless of the gain setting. Slide brake worked fine and showed output.

The dealership then replaced the brake control module, stating that they found that the slide brakes were getting full voltage, but the pedal brakes were getting less than half voltage. This worsened the problem; once again I am getting "trailer wiring fault". The slide brakes only work intermittently now, and when they do work they tend to catch, release, catch, release quickly instead of engaging smoothly as expected. The pedal brakes showed one bar of output ONCE, and it got stuck on that one bar even when I wasn't braking and was pulling forward. Since then it has never shown any bars of brake output when I use the brake pedal, regardless of gain settings.

I have tried trailer brake effort on every setting. I have deleted / re-set-up my trailer countless times. Two other oddities: 1) in the trailer menu, it said that I had towed my trailer for several hundred miles, which simply isn't possible; I've only putzed around town with it trying to fix this thing. I haven't gone on a big trip ever. 2) Since the last fix, my truck thinks the trailer blind spot distance is 33,000 and some change feet, even when I reset my trailer's measurements. This used to work.

A Curt Echo seems to work but is sketchy as hell, I don't want to brake with my iPhone, and I want to use the fancy towing features that I bought my truck for. I bought it just to test y'all's theory and then returned it.

After my last complaints, the dealership consulted with a Ford engineer, who told them that it passes their trailer simulator test, that I will never see trailer brake output bars for the pedal brake unless I'm moving at high speeds (false btw, it lowers it at speeds below 11mphbut does not make it zero), and that their truck is working perfectly as designed, and that my trailer must be frying electronics in my truck.

The dealership service manager did me an absolute solid and switched out the rental they gave me for a '22 F150 with the integrated brake controller.... Guess what, it works PERFECTLY. It always shows one bar of brake output when pressing the brake pedal when stationary, and always shows brake output when pressing the pedal at speed. The slide brakes always show brake output and are always smooth, never jerky or catching/releasing/catching again. It shows brake output when it slows itself down in cruise control. There is no weirdness in the trailer menu re: blind spot distance or miles towed. It is horrifyingly obvious now that I've driven my trailer with a different truck that my truck has NEVER engaged the trailer brakes when I braked the truck - seriously, stopping is infinitely easier in the loaner.

I am feeling physically nauseous thinking about how dangerous of a situation I have put others in while towing. If I'd believed the multiple Ford dealerships and Ford engineer that told me there are zero problems and it passes their trailer sim tests, I'd be out there thinking I had brakes when I had none. People could die because of this. I've seen at least one other forum post where an engineer told someone to NEVER expect to see ANY brake output bars when they press the brake pedal on their F150, which just isn't true.

I am waiting to hear back from my dealership after sending them proof that the loaner works perfectly. I have filed a complaint with the NHTSA. The Ford rep who DM'd me has not been responding to my attempts at outreach. I am STILL stranded in a state that I was meant to leave on 2/18.

 

[UGADawg96]

Hi all, unfortunately the nightmare continues.

A Ford dealership found issues with my trailer wiring harness and replaced it. This seemed to solve the trailer wiring fault / trailer disconnected errors, but I still did not see any brake output bars displayed when using the pedal brake, regardless of the gain setting. Slide brake worked fine and showed output.

The dealership then replaced the brake control module, stating that they found that the slide brakes were getting full voltage, but the pedal brakes were getting less than half voltage. This worsened the problem; once again I am getting "trailer wiring fault". The slide brakes only work intermittently now, and when they do work they tend to catch, release, catch, release quickly instead of engaging smoothly as expected. The pedal brakes showed one bar of output ONCE, and it got stuck on that one bar even when I wasn't braking and was pulling forward. Since then it has never shown any bars of brake output when I use the brake pedal, regardless of gain settings.

I have tried trailer brake effort on every setting. I have deleted / re-set-up my trailer countless times. Two other oddities: 1) in the trailer menu, it said that I had towed my trailer for several hundred miles, which simply isn't possible; I've only putzed around town with it trying to fix this thing. I haven't gone on a big trip ever. 2) Since the last fix, my truck thinks the trailer blind spot distance is 33,000 and some change feet, even when I reset my trailer's measurements. This used to work.

A Curt Echo seems to work but is sketchy as hell, I don't want to brake with my iPhone, and I want to use the fancy towing features that I bought my truck for. I bought it just to test y'all's theory and then returned it.

After my last complaints, the dealership consulted with a Ford engineer, who told them that it passes their trailer simulator test, that I will never see trailer brake output bars for the pedal brake unless I'm moving at high speeds (false btw, it lowers it at speeds below 11mphbut does not make it zero), and that their truck is working perfectly as designed, and that my trailer must be frying electronics in my truck.

The dealership service manager did me an absolute solid and switched out the rental they gave me for a '22 F150 with the integrated brake controller.... Guess what, it works PERFECTLY. It always shows one bar of brake output when pressing the brake pedal when stationary, and always shows brake output when pressing the pedal at speed. The slide brakes always show brake output and are always smooth, never jerky or catching/releasing/catching again. It shows brake output when it slows itself down in cruise control. There is no weirdness in the trailer menu re: blind spot distance or miles towed. It is horrifyingly obvious now that I've driven my trailer with a different truck that my truck has NEVER engaged the trailer brakes when I braked the truck - seriously, stopping is infinitely easier in the loaner.

I am feeling physically nauseous thinking about how dangerous of a situation I have put others in while towing. If I'd believed the multiple Ford dealerships and Ford engineer that told me there are zero problems and it passes their trailer sim tests, I'd be out there thinking I had brakes when I had none. People could die because of this. I've seen at least one other forum post where an engineer told someone to NEVER expect to see ANY brake output bars when they press the brake pedal on their F150, which just isn't true.

I am waiting to hear back from my dealership after sending them proof that the loaner works perfectly. I have filed a complaint with the NHTSA. The Ford rep who DM'd me has not been responding to my attempts at outreach. I am STILL stranded in a state that I was meant to leave on 2/18.

I only see the trailer brake gain amount bar displayed on the center console when using the controller with my hand, never seen any bars using the brake pedal when hooked up to the TT.

 

[mlmarcum]

I only see the trailer brake gain amount bar displayed on the center console when using the controller with my hand, never seen any bars using the actual brake pedal when hooked up to the TT.

Hate to tell you dude, but then you're probably having the same problem I am - this '22 loaner shows brake output when I press the brake pedal. Granted, you gotta navigate to that screen, but you should be seeing it light up unless your gain is at zero. Take a look at this video of me testing it out on the '22.

I thought it just wasn't ever supposed to light up at first, but turns out that's not true - it just straight up wasn't braking on my truck with the pedal. I really think this is a scary dangerous widespread issue that Ford has swept under the rug / misinformed people about. No telling how many people are driving around with only slide brakes and not realizing it.

 

[UGADawg96]

Hate to tell you dude, but then you're probably having the same problem I am - this '22 loaner shows brake output when I press the brake pedal. Granted, you gotta navigate to that screen, but you should be seeing it light up unless your gain is at zero. Take a look at this video of me testing it out on the '22.

I thought it just wasn't ever supposed to light up at first, but turns out that's not true - it just straight up wasn't braking on my truck with the pedal. I really think this is a scary dangerous widespread issue that Ford has swept under the rug / misinformed people about. No telling how many people are driving around with only slide brakes and not realizing it.

I have an XLT so I don't have the full electronic dash like that. If the brake controller output display via pedal use during normal driving is buried in one of the menus, then I'll have to take a look tomorrow. I've never looked for it in the menus, but after having the brake controller software recall completed last year, it's been solid. We're hooking back up in the morning and taking the TT out on a 300 mi trip, so I'll have an opportunity to check for the menu option.

 

[mlmarcum]

I have an XLT so I don't have the full electronic dash like that. If the brake controller output display via pedal use during normal driving is buried in one of the menus, then I'll have to take a look tomorrow. I've never looked for it in the menus, but after having the brake controller software recall completed last year, it's been solid. We're hooking back up in the morning and taking the TT out on a 300 mi trip, so I'll have an opportunity to check for the menu option.

Oh, word, I gotcha - it is indeed buried in the menus. I have the XLT without the fancy dash as well on my actual truck - mine has the tiny rectangle screen. If memory serves it's something like menu -> towing -> trailer info (?). That way you'll see the brake output bar all the time. It won't pop up by itself on the pedal brakes like it does when you use the slide brake, you gotta dig for it.

Nice setup! Hope your trip goes well!

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