Pro Power Ground Fault when its wet out

[FordRetiree]

Hi everyone. Tried searching on this topic before posting, sorry if I just didnt find my answer - I WAS getting non-stop ground fault error every drive cycle during the recent huge snow melt period. MY25, had it 6 months, totally no issue til just now. It's in the cab/front area, i can keep the rear outlets powered without tripping, but trying to reset the cab/front immediately retrips. I scheduled dealership visit (tomorrow), and then of course, it stopped couple days ago.
Will dealership be able to find anything - what is others experience? I saw some posts similar to this from a few years ago, but nothing recent. Evidently there was some TSB in 24, and then seems pretty quiet. I have the fordpass record that shows the issue existed repeatedly - i think i have 40+ alerts.

Sponsored

 

[Firn]

Iirc the regular F150s were having similar issues and it was traced to a connector in or near the rear wheel well.

I dont remember the details, I just remember reading about it some time ago.

Google response.

he F-150 Pro Power Ground Fault Issue
Yes, there is a well-documented issue with the Ford F-150's Pro Power Onboard system triggering ground fault errors due to moisture.
The Cause
The problem typically stems from the electrical connectors located underneath the truck bed, near the rear bumper where the Pro Power inverter box is mounted.
Water Intrusion: These wiring harnesses and connectors are exposed to the elements. During heavy rain, snow, or even trips through a car wash, water can seep into connections that weren't perfectly sealed from the factory.
System Sensitivity: The Pro Power system is highly sensitive to safety hazards. When moisture bridges the gap in these unprotected connectors, the system detects a leak in current, throws a "Ground Fault" warning on the SYNC screen, and shuts down the circuit to prevent damage or electrocution.
Common Solutions
Owners and dealerships have handled this issue in a few different ways:
The DIY Weatherproofing Fix: Many owners have successfully resolved the issue by locating the exposed connectors under the rear of the truck, unplugging them, blowing them dry with compressed air, and packing them with dielectric grease. They then wrap the connections tightly in electrical tape to create a watertight seal.
Dealership Harness Replacement: In cases where the moisture has caused corrosion or a dead short from a wire harness rubbing against the bed mount, dealerships have had to replace the affected wire harnesses entirely under warranty.
Checking Frame Grounds: Occasionally, the issue is caused by frame grounds that have started to corrode. The fix involves removing the grounds, cleaning the contact points with a wire wheel, and sealing them with silicone.
(Note: There was also an unrelated software bug on earlier models where simply pressing the "Test" button on the SYNC screen triggered a ground fault error, but Ford addressed that specific glitch via an Over-The-Air software update.)

 

[FordRetiree]

ok thanks for this info. I guess i'll still go to dealership tomorrow, maybe they know where to shoot some water to check the system. or at least the usual checks and precautions to do.

 

[chl]

So many vulnerable wires and connectors under the truck and elsewhere. When the weather gets better (warmer and dryer) and before the mosquitoes emerge, I plan on crawling under there and taping up whatever looks like it could use it.

 

[rtk11226]

Does anyone have a diagram or pictures of these connectors? I was having this exact problem about a year ago… dozens of errors and then nothing for days or weeks and then another random burst of errors. I always assumed it was a loose connection but every time I was about to head to the dealership the problem would clear. Haven’t had it reoccur in months.
thx

 

[chl]

Does anyone have a diagram or pictures of these connectors? I was having this exact problem about a year ago… dozens of errors and then nothing for days or weeks and then another random burst of errors. I always assumed it was a loose connection but every time I was about to head to the dealership the problem would clear. Haven’t had it reoccur in months.
thx

Might be this one in this thread:


https://www.f150lightningforum.com/forum/threads/unplugged-wiring-harness.34872/#post-646432

 

[chl]

Here was another connector problem - corrosion:

https://www.f150lightningforum.com/...-u019b-fixed-post-45.33226/page-3#post-628878

 

[FordRetiree]

An update for any future people that have this issue.
1) Truck went to dealership but the issue went away while they had it. They flashed the SODBC but that did nothing. Problem came back next rain.
2) This time around, the issue isnt going away when it dried out. Truck back at the dealership, currently a full week there. They've been trying something, I've gotten 171 Pro Power Ground Fault Error messages on the Ford app this week. They've replaced the DCDC as part of this, not sure what else. On the 5th day at the dealership they are opening a hotline ticket. Kind of wished they had done that earlier.

I'll come back with an update in a week or so. I had a difficult week to navigate without my truck, and no loaner. Cancelled weekend plans, sucks.

 

[chl]

An update for any future people that have this issue.
1) Truck went to dealership but the issue went away while they had it. They flashed the SODBC but that did nothing. Problem came back next rain.
2) This time around, the issue isnt going away when it dried out. Truck back at the dealership, currently a full week there. They've been trying something, I've gotten 171 Pro Power Ground Fault Error messages on the Ford app this week. They've replaced the DCDC as part of this, not sure what else. On the 5th day at the dealership they are opening a hotline ticket. Kind of wished they had done that earlier.

I'll come back with an update in a week or so. I had a difficult week to navigate without my truck, and no loaner. Cancelled weekend plans, sucks.

Bummer.
The first place they should look is the cab/front PPOB wiring and receptacles.

While wiring issues are hard to trace sometimes, that should be straight forward testing for a short hot-neutral and hot-ground. The neutral is bonded and grounded so a ground fault should indicate a short to ground providing a second path back to the inverter through ground.

A short circuit would also trip the breaker and the truck might report that as a 'ground fault.'

The front/cab outlets are on a different DC-AC inverter from the bed so they should also check that inverter for a problem tracing the wiring from the converter to the outlets.

Since it happen when wet, likely some wire or connector that could be exposed to possible water intrusion.

They should be able to easily remove the receptacles and look for loose wires that could be shorting out, but unless water could get to the outlets, maybe the ones in the Frunk(?) more likely a connector under the frunk somewhere that can get wet.

Hope they figure it out, but they are not electricians, and this is kind of an electrician issue, lol.

But not funny not having your truck because of it.

Not sure the DC-DC converter would be involved unless the 400VDC is stepped down before being fed to the DC-AC inverter. I think if the DC-DC converter were bad, there would be a lot of other issues, with the 12v system for example.

 

[FordRetiree]

Yep to all of that. It was pretty obvious to isolate the two halves of the system through the interface. The whole system would trip but the rear could be turned back on - front couldnt without retripping (also I already know how it works because I used to work at Ford). They did finally change the entire outlet in the frunk, to no avail. Also agree on DCDC - I feel like probably they replaced the inverter but mistakenly called it the DCDC. Not sure. It now happens all the time regardless of wet, so guessing the wetness led to corrosion. Still dont have it back, still driving a loaner. First gas truck in 5 years, and thats a wild experience too. Shifting, engine noise, standing at gas pumps, feels like a caveman.

 

[chl]

Yep to all of that. It was pretty obvious to isolate the two halves of the system through the interface. The whole system would trip but the rear could be turned back on - front couldnt without retripping (also I already know how it works because I used to work at Ford). They did finally change the entire outlet in the frunk, to no avail. Also agree on DCDC - I feel like probably they replaced the inverter but mistakenly called it the DCDC. Not sure. It now happens all the time regardless of wet, so guessing the wetness led to corrosion. Still dont have it back, still driving a loaner. First gas truck in 5 years, and thats a wild experience too. Shifting, engine noise, standing at gas pumps, feels like a caveman.

Gotcha, I sympathize, I can't imagine driving an ICE truck again!

Yes, there have been some cases of corrosion on connectors, could also be damaged wiring of course - insulation exposing bare wire shorting to the chassis for example.

There was one behind the glove box that got damaged in another post.

https://www.f150lightningforum.com/...ncetrac-1-pedal-drive-fault.35395/post-658278

Wiring issues are a pain to track down as you know and there are a lot of wire bundles on these trucks.

It'll be interesting to find out what went wrong in your case.

 

[FordRetiree]

well... no fix yet. dealer working with hotline evidently, doesn't sound like they have a clear path. i'm at the 30+ day mark on this repair. They are definitely trying, my phone blows up every other day with fordpass alerts about ground faults. what would you guys do?

 

[TaxmanHog]

Buy Back application should stimulate action.

 

[chl]

There was just another PPOB issue which was a connector problem, apparently driving on a dirt road had caused debris to get inside the connector and cause a connection problem with the neutral leading to a ground fault indication.

https://www.f150lightningforum.com/forum/threads/pro-power-service-required-help.36302/

The dealership "...helped take care of it and got a new harness and entire outlet box by reimbursing me and letting my local dealer handle the repair. I will say, to quote them “It was driven down a dirt road” and they were not kidding with all of the mud and rocks lodged in the underside. I have ripped a bunch of trim off to clean up the caked dirt. I need to remove more this summer as it is still crying dirt lol..."

Maybe you have some issue like that?

I have a whole list of wiring and connector issues with the Lightning from posts on forums etc.
Lots of potential for problems with all the wiring!

 

[FordRetiree]

well... never going to find out what is actually wrong. Ford is going to buy it back.




sigh.

Sponsored