Parking brake failed

[hturnerfamily]

per Ford: "The Ford F-150 Lightning has a parking pawl, a mechanical locking mechanism in the rear drive motor that prevents the wheels from spinning when the vehicle is in Park."

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[TaxmanHog]

 

[TaxmanHog]

Truck rolled/slid backwards while parked on hill

 

[RickLightning]

The rear tires lock, fronts do not. Just like Mach-E. Heavy vehicle, as you see in the video the tires are not moving at all. Answer is to clean surface and park on asphalt, or on flat driveway.

 

[jetfixr1]

The rear axle wiring issue was chafing with a component and is limited to gen14 gas F150's, not the Lightning. Perhaps you hit the ignition switch before putting it in park?

 

[Firn]

Very sorry to hear this, very glad you are ok.

That said, the failure of two independent mechanical safety systems, TWICE, seems exceedingly unlikely.

My guess is some combination of an angled driveway, snow and ice, and maybe including tires warmed from driving. It isn't helped by the fact that driving up the driveway would be with 4wd, but holding on the driveway only uses 2 wheels.

I'm interested to see what service says.

 

[MillieChliette]

Slid on the ice, 100%

The rear axle wiring issue was chafing with a component and is limited to gen14 gas F150's, not the Lightning. Perhaps you hit the ignition switch before putting it in park?

As others have already mentioned, it doesn't matter. The truck will automatically put itself into park.

 

[jefrank]

Yesterday I returned from the grocery store and parked my son’s truck in the usual spot and plugged it in. By the time I got back in front of the vehicle to get groceries out of the passenger side the truck began rolling back into the street. The charger pulled out of the port (connector is damaged and needs to be replaced). My son who is recovering from major surgery and limited on activity came into the garage and guided me to park again (we have had snow so wanted to make sure I was completely on a clear spot). I again put the truck in park, turned on the parking brake, vehicle was powered off. I walked around and got two bags of groceries with no problem, but when I went back to get the rest, as I was 1/2 way in the door bending to pick up stuff from the floor board, the truck again began to roll trapping me between the door and the vehicle. I was able to grab the overhead handle and step up on the running board as it rolled back into the street.
I had the dealership come and get the car. My son uses a different service department since the one at his dealership is inefficient, but that is further away. They may get to look at the truck by tomorrow. They don’t see any sensors off, but because I was honest, the sales manager said maybe it is my inexperience driving the vehicle or that it had a low tire pressure light last week, or the severe weather, all that sort of BS when a car guy talks to a woman. I grew up driving a split axle cattle truck so know how to drive and especially park.
Had I slipped (it was raining but hadn’t started to ice over yet) I would have been at least run over by the front wheel.
I am going to try and alert everyone because the service manager said he hadn’t seen any thing on any forum but I saw here that there have been recalls and some issue with wiring on the rear axle or something.
A vehicle in park with a parking brake activated should stay parked.
Regardless of the repair I am ordering an airline bumper or something like that and now refer to the vehicle as Christine (for you Steven King fans).

I have had 2 incidents where the e-brake did not prevent the vehicle from sliding down my driveway.

The first (last winter) caught me completely by surprise as I was about 15 feet away from the truck and away it went. Fortunately, it turned sideways and stopped itself before it could get stopped by trees.

The second occurred early this winter while I stopped (in park) to open the garage door to my barn. I was aware of the snow on the driveway and made sure the parking brake kicked in before I exited the vehicle. Still, before I could even get halfway to the garage door, the truck started sliding. Since I'd left the driver door open and the truck running I was able to jump back in and apply the brake, hard. The truck stopped sliding once the physical brake was applied. I've since added an opener to that garage door so I won't have to worry about it again.

It appears that the e-brake isn't sufficient to hold the vehicle under some circumstances, which is concerning.

 

[TMND]

Happened twice in a row (once in garage). And he’s not a stranger to the lightning. Pretty safe to say the OPs experience was not an operator error. Curious what the REAL cause was

 

[MaintGrl]

Dang . . THAT is scary!

 

[TMND]

Dang . . THAT is scary!

Now that I’ve actually watched that video I wonder how it would’ve behaved if he was parked the other direction…
It seems that when your foot is on the brake everything’s fine, but as soon as he releases the brake pedal, it started sliding immediately. So the front tires must start rolling a little bit and the back that’s locked just slides.

 

[NCevGuyF150]

Yesterday I returned from the grocery store and parked my son’s truck in the usual spot and plugged it in. By the time I got back in front of the vehicle to get groceries out of the passenger side the truck began rolling back into the street. The charger pulled out of the port (connector is damaged and needs to be replaced). My son who is recovering from major surgery and limited on activity came into the garage and guided me to park again (we have had snow so wanted to make sure I was completely on a clear spot). I again put the truck in park, turned on the parking brake, vehicle was powered off. I walked around and got two bags of groceries with no problem, but when I went back to get the rest, as I was 1/2 way in the door bending to pick up stuff from the floor board, the truck again began to roll trapping me between the door and the vehicle. I was able to grab the overhead handle and step up on the running board as it rolled back into the street.
I had the dealership come and get the car. My son uses a different service department since the one at his dealership is inefficient, but that is further away. They may get to look at the truck by tomorrow. They don’t see any sensors off, but because I was honest, the sales manager said maybe it is my inexperience driving the vehicle or that it had a low tire pressure light last week, or the severe weather, all that sort of BS when a car guy talks to a woman. I grew up driving a split axle cattle truck so know how to drive and especially park.
Had I slipped (it was raining but hadn’t started to ice over yet) I would have been at least run over by the front wheel.
I am going to try and alert everyone because the service manager said he hadn’t seen any thing on any forum but I saw here that there have been recalls and some issue with wiring on the rear axle or something.
A vehicle in park with a parking brake activated should stay parked.
Regardless of the repair I am ordering an airline bumper or something like that and now refer to the vehicle as Christine (for you Steven King fans).

Thanks for letting us know about this. This could be fatal.

 

[NCevGuyF150]

The parking brake is completely irrelevant. The truck has a park gear just like any other vehicle. It is not possible for the truck to roll away when in park. The rear axle is locked in place. Are you SURE you put it in park?

I wonder if the gear interchange switch could be bad

 

[evowner]

The parking brake is completely irrelevant. The truck has a park gear just like any other vehicle. It is not possible for the truck to roll away when in park. The rear axle is locked in place. Are you SURE you put it in park?

Since there is no cable from the shift lever to a gear that lock the axle, there is likely a solenoid or servo that engages the locking mechanism. So if that were to fail it would not work. I wonder if the OP has made any changes using the forscan tool.

 

[Grumpy2]

ome issue with wiring on the rear axle or something.

It seems to me the OP's comment might be the correct, either with the switch, wiring, or connections allowing an intermittent connection. Looking forward to the report from the dealer.

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