22 trailer brake controller

[JohnsonEJ23]

Thanks, Mctaf! Gosh, is it possible that a wire isn't actually missing and maybe just a fuse is missing? Does anyone have a wire schematic that would show which connector pin on the fuse block goes to which fuse slot?

 

[JohnsonEJ23]

Thanks, Mctaf! Gosh, is it possible that a wire isn't actually missing and maybe just a fuse is missing? Does anyone have a wire schematic that would show which connector pin on the fuse block goes to which fuse slot?

Never mind... I just remembered that the wire was missing completely from the Molex plug going into the module by the pedals...

 

[varundev]

There is no fuse on the LIN wire. It's a data line to tell the module the switch is being pressed or the gain is being changed. What you did is fine.

There are many variations of the harness based on options installed.

Trailer brake are electromagnetic. The more current that is applied, the stronger of a magnet or becomes. That causes it to drag on the drum. Since the drum is spinning, the magnet gets dragged in the directing of rotation, which causes it to move and spread the brake shoes, which asked the brakes to the drum. So there are 2 wear points; the shoes and the magnet.

Glad you got it working. I bought the Expedition in early July 2025 since I blew the engine on my wife's 2016 Expedition. I guess too much meth injected will do that. I knew these vehicles could tow my treasurer, but didn't realize Ford would screw us over so bad with the harnesses. My wife said "we have a trip coming up we have to tow for, you're an engineer, figure it out." So I did. In 2 weeks I had the trailer brakes working, tested, and verified during a short 3 hour trip. That's when I joined and told you guys what I found.

 

[varundev]

I also got the obd info displaying on the radio. That's really useful while towing to make sure temps stay in check.

 

[JohnsonEJ23]

I also got the obd info displaying on the radio. That's really useful while towing to make sure temps stay in check.

Neat. How did you get that to work?

 

[Langer]

I just ran a new LIN wire from the switch to the module last night and it fixed it to where the switch now interacts with the vehicle! A huge thank you to "96s10383"!!! I didn't have a chance to throw a multimeter on the trailer hookup to make sure it's actually doing what it is supposed to be doing, but as long as there are no other missing wires in the factory setup, I'm optimistic this will have been the missing link. I'm traveling for work this week, so I'll have to do that final test after I get back. It's great to now understand that I'm not crazy and wasn't doing something wrong this whole time!

What size molex pin did you use? I guessed blindly on Amazon and it looks far too big.

 

[JohnsonEJ23]

What size molex pin did you use? I guessed blindly on Amazon and it looks far too big.

This is from my Mouser.com order. I ordered a replacement plug too as I broke a plastic prong off of it learning how to get the pins out of it.

Mouser #:
538-34927-0140
Mfr. #
34927-0140
Desc.:
Automotive Connectors
Automotive Connectors GEN Y
ASSY RCPT 14 CKT HYB BLK
POL A

Mouser #:
571-2035334-1
Mfr.#:
2035334-1
Desc.:
Automotive Connectors
Automotive Connectors
Contact female0.64 20 to 22
AWG

 

[varundev]

Neat. How did you get that to work?

I used a Bluetooth adapter and OBD Fusion. I had to get the Ford PIDs to get some values. Then Android Auto will display it on the screen. The first time, I had to have the app open before I connected Android Auto.

There's no gauges, just values printed out. And it polls sort of slow. I'm working on getting it to update faster.

 

[Langer]

Here's where I currently stand:

I've purchased the following parts:

• Trailer Brake Switch: ML3Z-14529-AC
• Jumper Wire: NL1Z14A411F
• Trailer Brake Module (With Pro Trailer): ML3Z19H332J
• Pro Trailer Knob: ML3Z19H540AA
• Dash Panel to support pro trailer knob install: NL1Z7804339CA

I've received and physically installed everything successfully. Now I just need some help figuring out Forscan settings. I'm theorizing that there were some changes in how this works starting with the 2022 model year. I did find only, one, single person in a Facebook forum that says he was able to do the brake controller setup successfully and committed to finding me the Forscan settings he changed. I'm still waiting to hear back from him tough. I've tried to enable every setting I can find in Forscan related to trailer brake, but it isn't cutting it. I'm wondering if there is a change in the AsBuilt section that needs to happen that isn't updated in the "easy" section yet. I'm brand new to Forscan, so if anyone knows more about it than me, I'd love help getting on the right track!

I'd love to get this figured out on my vehicle and get it all documented for others to be able to follow too. I'm really surprised at how hard this has been to figure out and have run across many others who are also struggling with it. I'm mainly trying to get the trailer brake controller figured out first and will then focus on the Pro Trailer backup feature after that.

Sorry to keep pestering your post. I just bought a 2023 and am working with the dealer to add the TBC and other goodies like you’ve posted about. Did yours already have a trailer brake module, but you bought the new one so you could have pro trailer?

 

[JohnsonEJ23]

Sorry to keep pestering your post. I just bought a 2023 and am working with the dealer to add the TBC and other goodies like you’ve posted about. Did yours already have a trailer brake module, but you bought the new one so you could have pro trailer?

No worries at all! Ours had a controller module and port on the back, but no switch on the dash for manual control and to adjust the gain.

 

[JohnsonEJ23]

I did get a new module because I wanted one that would work with the pro trailer backup too. I'm not sure if the stock module would have worked with the switch as when I was trying it, the wire was missing...

 

[varundev]

If you got a vehicle with Standard Tow, the dealer likely won't be able to do anything because you're likely missing the wiring in one of 3 harnesses.

The Standard Tow Trailer Module also doesn't support electric brakes. You have to get the other Trailer Module.

You will likely have to do a couple things if you have Standard Tow.

1. Check where you're missing the LIN wire. Then add it in.
2. Get the Pro Trailer Trailer Module.
3. Get the Trailer Brake Switch.
4. Get the Trailer Brake Switch harness.
5. Use Forscan to program.

If you got an aftermarket brake controller harness with the truck, you likely have Standard Tow. It's a Grey connector ending in 4 bare wires. Check the glove boxes or rear storage bin.

 

[Mctaf]

Varundev helped me with my 2022 - he's extremely knowledgeable. I agree that the dealer probably won't be able to help. If they look up your VIN for parts, controller etc, it will show the one you have, not the one you need. They'll run into a roadblock with the wire missing in the harness and will conclude it can't be done on your vehicle like others have reported. I had gotten the service manual with wiring diagrams and followed the info that Varundev provided. This subject has been going on for almost a year? When I finally got all the pieces together including the programing (thanks to Varundev) I look at it and say, that was way too simple.

 

[Langer]

Just got all my parts.

Here goes nothing!

 

[Langer]

Just for reference, here is a link I used to reference Forscan info: https://www.f150lightningforum.com/...y-trailer-brake-controller-to-24-flash.25522/

Do you think all of these manual changes to “as-built” were required, since it was discovered root cause was the missing LIN wire?

Would the drop down “easy” mode have worked if the LIN wire was present?

Or all of those were pieces of the puzzle that needed remedy?

 

[Left Coast Geek]

reading this makes me quite happy I spent the months shopping for a 2019 that came with the HD tow option. That year, the Limited Stealth package included it, it was special order on any other package. I did see one XL 'fleet' version that was totally stripped of nice stuff, but had HD Tow.

 

[Langer]

reading this makes me quite happy I spent the months shopping for a 2019 that came with the HD tow option. That year, the Limited Stealth package included it, it was special order on any other package. I did see one XL 'fleet' version that was totally stripped of nice stuff, but had HD Tow.

I bought mine instead of one with HD tow 30 miles away because the Dealer told me they could add it. it’s been a whole thing.

 

[JohnsonEJ23]

Do you think all of these manual changes to “as-built” were required, since it was discovered root cause was the missing LIN wire?

Would the drop down “easy” mode have worked if the LIN wire was present?

Or all of those were pieces of the puzzle that needed remedy?

It's possible. I messed with my setting so much prior to adding the wire, I have no way of knowing. Did you get yours working?

 

[Langer]

It's possible. I messed with my setting so much prior to adding the wire, I have no way of knowing. Did you get yours working?

I accidentally ordered the wrong trim piece. Maybe Monday or Tuesday.

 

[GaryW1969]

I joined just for this thread.

I just went through this. I have a 2024 Expedition XLT Max which I bought a bit quickly. My 2016 Expedition engine failed and I needed a tow vehicle. I went out, looked for a newer Expedition, looked for a hitch and 7 pin connector, and bought it. In the 2016, I just needed to install the dash switch and I was good to go. Not so much with the 2024.

I found out I only had the Standard Tow package and figured I needed the switch and maybe a harness and module. The one guy didn't have the brown/white wire and I was missing that from C238 to C214, so I bought the repair kit to add the terminals and some wire to add it to the harness. On the day of install, I took the entire dash apart and came to find out I'm missing ALL the wires needed from the TRM under the dash to the brake switch. Looking in Ford's part catalog, there are more than 30 harnesses available depending on options installed. So, I custom designed a harness, ordered the switch and got everything installed. Using Forscan, I made some changes to enable the brake switch. I was able to get the car to recognize the brake switch and gain settings, but it would not apply power to the 7 pin connector electric brake pin and I was getting a trailer not connected error. So, I ordered the other module, installed it, and everything works. No additional programming at this time, but I know they're are errors in the module based on Forscan output. I have to tow tomorrow and am not taking a chance on bricking a brand new module. I'll try when I get back.

If someone really cares to do all this, I can post part numbers needed and harness design details. It's a very involved task and greatly depends on which instrument panel harness you have.

I'm thinking about making a kit with instructions for those who definitely want the factory installed look. I did not want to hang an aftermarket brake controller in the vehicle.