Never thought about it…? Brake lights

[PFree]

This could be really dumb but my daughter and I were traveling I-10 using Blue Cruise. A slower car in the left lane merged unexpectedly and my truck slowed rapidly as it should have. My daughter asked if the brake lights came on while we slowed down. Honestly I don’t know. Anybody?

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[Heliian]

If you search through the forum you'll find a couple of discussions regarding the brake light activation thresholds.

The short of it is, yes, the brake lights come on at a set level of deceleration whether you're on the pedal or not.

 

[TaxmanHog]

Yes, most likely they came on

 

[hturnerfamily]

at least for the 2022 version Lightning, no, they do not... unless YOU press the brake pedal, or you are on 1Pedal, the brake lights do not illuminate purely on 'regeneration' slowing... no matter the speed or intensity...

but, while I say all that, what you are asking about is whether the truck's SAFETY "follow distance" Mode, in this situation, is going to APPLY the brakes, physically, to then illuminate the brake lights...well, probably, but it's also dependent upon the intensity of the 'slowing' that is needed, in each situation.

If the truck simply removes itself from 'Cruise', and allows the current DRIVE MODE regeneration to slow it, enough, then no...but, if the severity causes the truck to also apply the brakes, then, yes. Also, if you have 1pedal ON, then, yes, it will then ALWAYS apply the brakes, physically, and, therefore, the brake lights.

The simplest and easiest method to use to find out 'how' it works, is to go out at night, where you can SEE your brake lights in your mirror, when and if they illuminate.

 

[TaxmanHog]

A slower car in the left lane merged unexpectedly and my truck slowed rapidly as it should have.

Disregard the opinion above, your light came on in an emergency style of braking.

 

[Adventureboy]

Yes, they come on upon deceleration past a specific set point. You can see them light up in the driver's side mirror when it isn't sunny. In 1PD they are always on if your foot is off the accelerator, in 2PD always on when your foot is on the brake. If you ease off the accelerator in 1PD, they won't come on until deceleration exceeds the threshold. In your case, they definitely would have come on when the truck had to decelerate.

@Ford Motor Company, it would be good to indicate brake light activation on the instrument cluster. It would take the guesswork out.

 

[Lytning]

@Ford Motor Company, it would be good to indicate brake light activation on the instrument cluster. It would take the guesswork out.

I second your suggestion to @Ford Motor Company. We have a Lexus RX-350h Hybrid which has a brake indicator on the dash instrument cluster. It is indeed very useful when you have someone tailgating you ... which is all the time around metro Atlanta.

 

[Karlos]

at least for the 2022 version Lightning, no, they do not... unless YOU press the brake pedal, or you are on 1Pedal, the brake lights do not illuminate purely on 'regeneration' slowing... no matter the speed or intensity...

but, while I say all that, what you are asking about is whether the truck's SAFETY "follow distance" Mode, in this situation, is going to APPLY the brakes, physically, to then illuminate the brake lights...well, probably, but it's also dependent upon the intensity of the 'slowing' that is needed, in each situation.

If the truck simply removes itself from 'Cruise', and allows the current DRIVE MODE regeneration to slow it, enough, then no...but, if the severity causes the truck to also apply the brakes, then, yes. Also, if you have 1pedal ON, then, yes, it will then ALWAYS apply the brakes, physically, and, therefore, the brake lights.

The simplest and easiest method to use to find out 'how' it works, is to go out at night, where you can SEE your brake lights in your mirror, when and if they illuminate.

That used to be the case, but along with taking most of the regen away from the Sport mode, Ford has made the brake lights activate at a much lower deceleration threashold. I've seen this on both my 2022 LER and 2023 LER. I noticed the lack of brakelight activation several years ago while using full regen in Sport mode - it's not the same as built.

 

[Zprime29]

I use a very scientific measurement system to determine this:

If it makes you think, "Wow, it's braking hard...." then the brake lights came on.

Cruise essentially puts the truck in 1PD mode which as others have mentioned, uses a deceleration threshold to determine if the lights come on. My uneducated guess is that the threshold is slightly more than `coasting` in sport mode.

 

[JayF]

is a GREAT video on this topic. (Which led to https://www.consumerreports.org/car...provide-fair-warning-on-some-evs-a9533519285/)

At about 12:30 he starts in on how GM handles it: accelerometer registers you are stopping and enables the brake pedal.

I'm really curious how Ford handles it. I paid attention today when driving around, and I'm fairly convinced they have an accelerometer somewhere, too.

 

[Cvh8601]

is a GREAT video on this topic. (Which led to https://www.consumerreports.org/car...provide-fair-warning-on-some-evs-a9533519285/)

At about 12:30 he starts in on how GM handles it: accelerometer registers you are stopping and enables the brake pedal.

I'm really curious how Ford handles it. I paid attention today when driving around, and I'm fairly convinced they have an accelerometer somewhere, too.

I think i've read in this forum that Ford controls 1 pedal braking by maintaining constant g deceleration, so they must be monitoring acceleration.

No need for an actual accelerometer, that would probably be pretty fussy. Derivative of wheel speed (rotation rate) will do nicely with some calibration factor and probably requires less filtering than an actual accel. But who knows?

 

[Lytning]

I am certain our trucks have one or more accelerometers. My iPhone 15 is reported to have 3 of them.

 

[JayF]

Eh, accelerometers are pretty common, in a lot of stuff for a lot of reasons... including one+ in every phone and most laptops out there. Depending on the exact hardware package they use for the infotainment system in our trucks, it's even possible one is "free".

Ideally they are using multiple sources so it adds accuracy in the good case and redundancy in the bad cases. IDK, but I know it works well enough with 1-petal that I don't sweat it -- I did make a point to check after seeing that video from Technology Connections .

 

[Kev12345]

A nice software update would be some kind of visual indicator on the dash when brake lights are activated. Tesla does this.

 

[MidAtlanticLightningClub]

This could be really dumb but my daughter and I were traveling I-10 using Blue Cruise. A slower car in the left lane merged unexpectedly and my truck slowed rapidly as it should have. My daughter asked if the brake lights came on while we slowed down. Honestly I don’t know. Anybody?

Yes, the brake lights come on during any rapid deceleration. I’ve used the bed camera and filmed it at night in my 2022. You get the strongest braking that results in brake light activation when using the brake pedal and hard deceleration with 1PD but you can also get it with sudden braking in Blue Cruise or ACC/LC.

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