Trailer Camera and TPMS Stopped Working - Where is Fuse? I'm on the road Help

[Snooker_ML]

Help I'm on a long awaited RV trip driving the next 5 days Amarillo, Dallas , etc to Florida and can't research this easily. TIA.

Short question: Where exactly is the fuse for the round trailer connector for the harness for the rear trailer camera and TPMS? Pictures or details would be SO appreciated.

Long question:
I have a 2023 Powerboost and 2 years ago installed the LC3Z-1A189-A harness, camera and TPMS kit. (See https://www.f150gen14.com/forum/threads/2022-lariat-smart-trailer-tow-connector.11902/#post-315605 for details)

The TPMS is great and the rear camera is a MUST for me, I'm very worried to drive in traffic without it the next 1000 miles, not to mention backing up.

However, today they BOTH quit working. It happened after I pulled into a gas station and put it in reverse, which normally switches to the rear trailer camera but didn't this time. Then trying to manually select the trailer camera, which I do a lot on the highway, just shows the blue screen no camera symbol. The TPMS pressure just says not detected. The knob for the Pro backup still works but shows no camera images, and I never use the Yaw module features so I don't know if that is working.

Diagnostics: I know there was no recent damage to the wiring (like snagging on the hitch maybe), I then unplugged and reseated the connector. I turned the engine off and. Tried this several times over several hours. No change.

I figure since both Camera and TPMS stopped, that if it's not a connector problem, then maybe a fuse. But where? Which fuse box and name or number of circuit? I have a voltmeter and could also check pins on the "12 pin connector" at the truck bumper if I knew the details. No idea. Pretty sure the trailer is not the problem, not the wiring or connector. If you can't find an answer can you get me close to the correct URL maybe?

I have an OBDLink MX+ and ran the diagnostics but didn't expect much and didn't get much.

1. I can try a dealer but have no time to schedule an appointment. If I could talk them into a quick OBD scan do you think it could pinpoint a fuse or anything else?

2. I thought maybe a dealer would have another F150 with the special connector and I could plug my trailer into it and verify the trailer is ok.

What do you think? Any ideas I'm desperate. TIA

Sponsored

 

[Snooker_ML]

 

[Buyer2021]

FWIW, attached are the only two wiring diagram cells I find that are specific to the cam / TPMS system.

This from the Workshop Manual for a 2022 F150 and indicates that Battery Junction Box (the big fuse box under the hood) Fuse F25 (10A) is the only power feed to the TPMS/cam connector.

Also attached just FYI is the C439 diagram, this is the connector that plugs into the back of the '12-pin' tpms / cam socket on the bumper. It shows the wire to Fuse 25 on pin 1.

Note that pin 6 is the ground - the white 18ga wire goes to a bolt / ground-point under the rear chassis, driver's side - be sure to verify that's intact (required for a complete 12v power circuit for the TPMS / cam).

Given the interchangeability of the TPMS / cam kits for all gen 14 F150 years and engines, I suspect all of this will be valid for your 2023 PB.

Hope that helps, please keep us updated, Good Luck!

EDIT to add Battery Junction Box diagram showing Fuse 25 location:

 

[Bobcatou]

To see if it a fuse, you can also check pin 4 of the regular trailer plug. That is the 12v accessory pin and I am guessing that is the same power source. My fuse popped on that already once.

 

[Snooker_ML]

I think I found it. The owners manual built-in to Sync helped me find fuse 25 in the engine compartment, since there is nothing in the fuse lid showing anything at all. It was indeed blown!

It's raining or I would have swapped a different one in for 25 just to see. I'll wait until morning but I'll sleep well.

The description for 10A mini fuse 25 is:
Center high mounted stoplamp camera. 2 kw inverter. 24v alternator - run/start feed. Analog rear video camera.

Some fuse locator resources:

https://fuseandrelay.com/ford/f150-14g.html

https://www.startmycar.com/us/ford/f-150/info/fusebox/2023

 

[Snooker_ML]

I was out looking while you posted. Yes I think it wasn't that complicated after all.
I'll let you know! Thanks for your quick response, never could have got that from stopping at a dealer I feel.

 

[Bobcatou]

Took 3 days for a dealer to figure out my accessory plug issue was the fuse. I had them deal with it cause I was having other things addressed. I shouldn't have bothered and trouble-shooted myself.

Glad you figured it out.

Nice fuse reference sites by the way

 

[loder]

I think I found it. The owners manual built-in to Sync helped me find fuse 25 in the engine compartment, since there is nothing in the fuse lid showing anything at all. It was indeed blown!

It's raining or I would have swapped a different one in for 25 just to see. I'll wait until morning but I'll sleep well.

The description for 10A mini fuse 25 is:
Center high mounted stoplamp camera. 2 kw inverter. 24v alternator - run/start feed. Analog rear video camera.

Some fuse locator resources:

https://fuseandrelay.com/ford/f150-14g.html

https://www.startmycar.com/us/ford/f-150/info/fusebox/2023

yes! thank you for the fuse diagram sources.

 

[Bobcatou]

Odd, I just checked my fuse box compared to the picture above and there is no fuse in that spot. I wonder if I will be adding one, once I install my trailer camera.

 

[Snooker_ML]

Micro2 fuse. Fixed!

 

[Snooker_ML]

No because my rear truck bed camera also went out, which is located at the high brake light.

 

[Buyer2021]

To see if it a fuse, you can also check pin 4 of the regular trailer plug. That is the 12v accessory pin and I am guessing that is the same power source.

Sorry, bad guess.

The 12v pin on the 7-pin 'umbilical' connector is a separately fused higher-current circuit.

 

[Bobcatou]

Sorry, bad guess.

The 12v pin on the 7-pin 'umbilical' connector is a separately fused higher-current circuit.

 

[Snooker_ML]

Well there's more...
The trailer camera and TPMS both went out and both were fixed when the fuse was fixed.

But then a couple days later during a rainstorm I got a Fail message that the TPMS stopped working. The message is a new thing. And it hasn't worked again for 2 days. Any ideas?

 

[Snooker_ML]

I am reporting that I found the fault in the TPMS system. A wire got cut near the hitch and it's fixed now. My awesome ProPride hitch has a plate and during a very sharp turn it pinched the wire. Thankfully it was easy to find.

Sponsored