Any update on a Trailer TPMS system?

[Calson]

TPMS was mandated by the feds as an easy way to minimize under inflation that results in poor fuel economy - nothing more. It is not a safety feature.

Big rigs pulling heavy trailers do not have a TPMS and the expectation is that the driver will check tire pressures as needed.

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[Buyer2021]

TPMS was mandated by the feds as an easy way to minimize under inflation that results in poor fuel economy - nothing more. It is not a safety feature.

Big rigs pulling heavy trailers do not have a TPMS and the expectation is that the driver will check tire pressures as needed.

Certainly, a trailer TPMS doesn't relieve one of the duty to regularly check and maintain proper trailer tire pressures, bearing adjustment, alignment, etc.

But a TPMS with temps can give early notice of many types of punctures and other wheel / tire issues that can and do arise while towing - often allowing corrective action before the situation becomes worse in terms of safety and / or equipment damage.

Maybe not "a safety feature" but a welcome tool for monitoring rig status in the real world of trailer towing.

 

[BrewDay09]

New member here but I have read through this entire post and many others and mine seems like a different issue than others.

I have a new 2024 Lariat 501A with 360 cameras and tow package. It has the aux trailer camera blue screen and trailer TPMS in the MyView. So I bought the F-250 camera kit with TPMS thinking I would just tie into the 12-pin connector hiding behind the bumper like so many threads discuss. However, the harness on my truck does not have any 12-pin connector at all. The part number on the harness is RL3T-13A576-TCF.

The C423 connector has all the trailer camera/TPMS/Yaw wires on the vehicle side, but they don't continue to the bumper side. Again, there is no 12-pin connector on my harness at all. This may be a "feature" of the 2024 model year or maybe they intended for a camera and TPMS to be connected a different way.

Vehicle side of my C423 connector:

Bumper side of my C423 connector:

Pins on bumper side of C423 connector.

Does anyone know if there is a harness for the 2024 that can be purchased that has the 12-pin connector with camera/TMPS? Is there a new way to connect a camera and TPMS that I am missing? Or should I plan to re-pin the C423 connector and make a patch cable with the female 12-pin plug? I hope others with more experience with this vehicle can comment.

Thanks in advance.

 

[Buyer2021]

mine seems like a different issue than others.

See the the below diagrams (for 2022 MY). Are you saying you do not find C439 (in the harness between C423 and the 7+4-pin or 7+12-pin bumper sockets?

Also shown in this pic:

Was your truck OE with the 7+4-pin bumper sockets, or the 7+12-pin bumper sockets?

 

[BrewDay09]

See the the below diagrams (for 2022 MY). Are you saying you do not find C439 (in the harness between C423 and the 7+4-pin or 7+12-pin bumper sockets?

Correct. There is no C439 connector on mine. I was just reading about a DIO for customer installed camera and TPMS. My truck didn't come with that and suspect that they are now using a cheaper harness when that option is not selected.

Was your truck OE with the 7+4-pin bumper sockets, or the 7+12-pin bumper sockets?

The truck came OE with the 7+4-pin bumper socket. The F250 camera/TPMS kit I bought has the 7+12-pin bumper socket.

I think I found a harness that provides the 12-pin C439 connector part number ML3Z-13A576-PN. It appears to be backordered. I may just do the re-pin and make a patch cable to connect to the back of the 12-pin bumper socket.

 

[Buyer2021]

The truck came OE with the 7+4-pin bumper socket. The F250 camera/TPMS kit I bought has the 7+12-pin bumper socket.

Correct. There is no C439 connector on mine. I was just reading about a DIO for customer installed camera and TPMS. My truck didn't come with that and suspect that they are now using a cheaper harness when that option is not selected.

Could be I guess, though the DIO TPMS/CAM option was in the 2022 Order Guide when I bought mine which came with C439 even though I didn't order that DIO option (because I was counseled that it would likely cause a delivery delay).

Just never any accounting for Ford's whims, is there?

Good Luck!

(Be sure to help fellow 2024 owners out by posting the full saga with pics and any needed PNs in this thread when you get it figured out)

 

[BrewDay09]

An update on the effort to DIY the harness. Success!

I was able to re-pin the bumper side of the C423 harness and add a pigtail with a new 12-pin C439 Molex connector. I also included the wires for yaw sensor (though not needed) and TPMS (which I am using) along with the camera wires. Here is the process and parts used.

I created a pigtail with a Molex connector bought on Digikey (0334721201) and pins (0330123002) plus some multi-colored wires bought on Amazon. I created a spreadsheet to match the colors of the wire I bought to the colors in the circuit diagram above.

The pigtail only needs to be 2-3 feet long. Note that the black wire is 18 gauge while the others are 20 gauge. This is the ground wire and it also needs to be a bit longer.

The C423 pins looked like this before re-pinning. The slots with no pins have a plastic dummy pin to allow sealing at the silicone gasket on the backside. These need to be removed.

The other end of the pigtail wires get 1.5 mm male pins. I originally purchased a part number from Digikey that I found in a different forum. This ended up being too small and I could not figure out the correct part number from the 3,289 different connectors on Digikey. I ended up buying a multi-pack of automotive connectors on Amazon and one of them was the right fit. I believe it was 611-1.5B.

The connector pin (one of the existing ones in the connector) looks like this which is slightly longer than what I installed. If someone knows the correct TE AMP part number, please add it and I will update this post.

The pigtail was attached to the connector like this.

When done the pins now look like this.

I attached the ground wire to the chassis ground location that the parking harness was already connected to (shown here before I added my wire).

At the end of several days of fussing and waiting for parts, the DIY worked, so I can confirm that the wires on the truck side of the C423 connector are correct and active. Overall, this DIY is not a project for the faint of heart. I give it about an 8/10 in difficulty and it took me probably 10 hours in total, much of which was spent lying on my back under the truck. You also need de-pinning and crimping tools and know-how to get the connectors apart.

Here is the view out the back of my enclosed car trailer. The TPMS module is also recognized by the truck.

Getting the replacement parking sensor harness which already has the 12-pin C439 is definitely the preferred way to go. The one I think is correct (ML3Z13A576PN) was out of stock when I needed it and I can't confirm this is the right one either. If someone has purchased this, please post your results.

 

[Buyer2021]

An update on the effort to DIY the harness. Success!

Kudos and thanks for the detailed post. ?

IMO it's a real pity and PITA that Ford continues to deliver trucks without complete provisions for their own accessory trailer cam / TPMS kit (which IMO should be a straightforward plug-and-play installation on all trucks with 360 cams and any tow package).

But at least, thanks to members like you, we can all enjoy the benefits of those features.

(in spite of the somewhat different DIY effort required on my 2022 500A, I really appreciate having the integrated trailer TPMS / rear cam on my rig )

 

[DadBald]

Had some clarifications to offer after I just called my dealership to ask about the bumper harness. @smarty39 asked about this a few pages back.

The current part number is ML3Z-13A576-PB. This is a "service number" (as they called it).
The part number ML3T-13A576-AKF is an "engineering number" (as they called it).
They both point to the same harness. They are just different codes for different tracking systems. The distinguishing factor is the T and Z in the 4th digit.

Current cost was $153, and they can have it in on Monday for me, so 2-3 business days

This thread is a wealth of information. Many thanks to all who have contributed. Hoping mine hooks up without a hitch (pun intended - see username).

 

[DadBald]

I'm being impatient... my trailer kits are here but I'm still waiting on my bumper harness.

Did I read that the trailer tire temperatures will not show up on 2021's with the small IPC screen? I made the FORScan change to activate the trailer TPMS view, but I can't view anything until I have the bumper harness and trailer wires all setup. The suspense is killing me!

 

[Buyer2021]

Did I read that the trailer tire temperatures will not show up on 2021's with the small IPC screen? I made the FORScan change to activate the trailer TPMS view, but I can't view anything until I have the bumper harness and trailer wires all setup. The suspense is killing me!

Yer gonna just have to take a chill-pill and see what you end-up with.

If this minor suspense is killing you there's certainly no reason to get prematurely excited one-way-or-the-other about what may or may-not show on your particular display.

 

[DadBald]

Crap. Thanks anyway

Just excited. I'll let you know when I get it up and running.

EDIT: Actually, I take that back. I blame Ford. This functionality is built-in, but they fail to put in a few wires which effectively disables it for everyone. Then they bury it for years and hide it behind dealerships who know nothing about it. And then, to get it working, the steps are:
1. your bumper electric hookups may or may not be right (12-pin or 4-pin)
2. your bumper harness may or may not be right (12-pin isn't even populated correctly, even if you had the blue Aux camera screen from the beginning - why is this here if there is no possible way to use it?)
3. your cameras may or may not work right, even if you enable them again and you had them back in 2021 before they were taken out by some update
4. your trailer TPMS display is hidden. And we don't even know if it displays temps or not when the sensors and software is clearly functional on some vehicles.

It's just all very odd. And every step of the way to reclaim the vehicles built-in functions is a crap shoot. Maybe this step will work, maybe the next step won't. And it's a big investment along the way if the last step happens to not work.

Frustrating, to say the least. But I'm well into it now, so we will wait and see I suppose.

EDIT2: Ok, I am also excited. And Impatient. And anxious I guess. All the things.

 

[Henfield]

I went with a Tymate TM7 unit off amazon for $30. The Ford system is way overpriced. Plus I got USB outlets as well.

 

[Buyer2021]

I went with a Tymate TM7 unit off amazon for $30. The Ford system is way overpriced. Plus I got USB outlets as well.

If you're happy with that, that's a swell solution, no worries!

Having BTDT for many years, the integrated solution makes me happier. Plus I got an integrated trailer rear-view cam as well .

Without apology, it's well-worth the price for some of us.

 

[Henfield]

If you're happy with that, that's a swell solution, no worries!

Having BTDT for many years, the integrated solution makes me happier. Plus I got an integrated trailer rear-view cam as well .

Without apology, it's well-worth the price for some of us.

Raises the question of why I am happy with it. Not only do you get TPMS but also it monitors tire temperature which in the event of impending failure would be the canary in the coal mine.

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