Adaptive Cruise Control / Brake lights

bravelion

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I can attest to how ACC works on my 2016 Grand Cherokee, which I assume will be the same on the JL Rubicon I've ordered (which I had to include the Advanced Safety Group specifically because I wanted ACC).

I rented a travel trailer and pulled it up into Colorado last summer. On the Million Dollar Highway between Durango and Ouray, I set the cruise to 30 mph on the slow twisty curves. On the steep downhills I was beyond impressed with the technology when I realized that the Jeep was hold hill descent speed using a combination of downshifting and brakes. In my side and rear view mirror I could see the reflection of the brake lights off the trailer when brakes were applied.

So I assume, even without towing a trailer, if a quick "collission avoidance" type of slowdown or stop was triggered, the brake would deploy and the brake light would come on. But on normal "take foot off the gas" slowdowns by the ACC, no brake light comes on because brakes are in fact not being used.

This is all speculation as to how it might apply to the JLUR w/ACC though.
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TxJeepers

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Yes, if the vehicle applies the brakes the brake lights come on.
I have ACC in my 18 Honda Pilot and in my 19 Rubi. I love using it in both. Though, based on my experience with two car manufacturers I can tell you that they are not all implemented the same or as well. FCA in the Jeep has got their system well polished and it really is a pleasure most of the time. It's a real smooth system while in the Honda it is very 'jerky'. When I run up on another vehicle in the Jeep or someone pulls into my lane the Jeep removes gas and slows accordingly, kind of like most of us would do. BUT, the Honda is all over the brakes with a sudden jolt. Pretty annoying. I think they designed it to be error on the side of caution a bit to the extreme while Jeep has it tuned more like we'd actually drive. Now mind you, if you get too close Jeeps forward collision mitigation will kick in and apply some serious braking. I know that works as well. LOL.
I speciually like have the ACC at night, bad weather etc, because its providing another layer of safety with its radar being able to see out in front and start slowing the vehicle if it sees something.
To the poster who ranted about this technology...why are you even on the JL forum bro? You can still find some quality TJs out there and they have a forum just for those.
 

Motoristx

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If ACC were used in Houston traffic, because of the gap it maintains, LOTS of cars would be jumping into that gap!
 

TxJeepers

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If ACC were used in Houston traffic, because of the gap it maintains, LOTS of cars would be jumping into that gap!
I'm from Houston and rarely use it in the heavy traffic. Even at one bar though, the Jeep does a good job of adjusting.

down to one bar line, it's pretty close.
Correct. Moderate traffic this is the setting i use. When it opens up though I like 3 bars.
 

Karl_in_Chicago

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If brakes are being applied, brake lights come on; if brakes are not being applied, no brake lights. Seems pretty simple - just like any other car I drive. I was once almost rear-ended in my office parking garage by a co-worker. Driving my 6-speed 'vette I pulled in to the entry lane/gate and put it in neutral and while leaning out of the car to smack my badge against the card reader I took my foot off the brake to reach. As soon as my brake lights went off she hit the throttle on her ginormous SUV and came thisclose to smacking my rear bumper. From some of the posts here I guess when I engage the clutch to coast and/or downshift my brake lights should be coming on? Or are too many people B.F. Skinner graduates conditioned by the illumination of brake lights to be the sole indicator of a vehicle's progress?
 
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jdegrave

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If brakes are being applied, brake lights come on; if brakes are not being applied, no brake lights. Seems pretty simple - just like any other car I drive. I was once almost rear-ended in my office parking garage by a co-worker. Driving my 6-speed 'vette I pulled in to the entry lane/gate and put it in neutral and while leaning out of the car to smack my badge against the card reader I took my foot off the brake to reach. As soon as my brake lights went off she hit the throttle on her ginormous SUV and came thisclose to smacking my rear bumper. From some of the posts here I guess when I engage the clutch to coast and/or downshift my brake lights should be coming on? Or are too many people B.F. Skinner graduates conditioned by the illumination of brake lights to be the sole indicator of a vehicle's progress?
Until we have Level 5 Autonomy as a proven, reliable technology then I don't propose depending 100% on any of the safety features on any vehicle to get you from point A to B or to keep one out of trouble. Driver is still responsible for the safe operation of the vehicle. The safety equipment is great but no replacement for an attentive driver.
 

UtahDirt

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This is intended for all those who shirk their responsibilities by handing it off to a new and unproven technology. I say it is YOUR RESPONSIBILITY to operate a motor vehicle. Don't be a drag on the rest of society by copping out with the "It's not my fault the technology failed" excuse. Forget about all that BS technology and do your job behind the wheel.
Yes dad, geez lighten up most would assume the brake lights would come on and most haven't been followed to see if they do.
 

UtahDirt

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I'm from Houston and rarely use it in the heavy traffic. Even at one bar though, the Jeep does a good job of adjusting.


Correct. Moderate traffic this is the setting i use. When it opens up though I like 3 bars.
Depending on speed if I use three bars , which I like, allows me time to open another beer. ;) it's just enough room for people to cut in front of me.
 

rickinAZ

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This is intended for all those who shirk their responsibilities by handing it off to a new and unproven technology. I say it is YOUR RESPONSIBILITY to operate a motor vehicle. Don't be a drag on the rest of society by copping out with the "It's not my fault the technology failed" excuse. Forget about all that BS technology and do your job behind the wheel.
I said the same thing 30 years ago about anti-lock brakes. Technology marches on.
 

Bri_BKT

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I have noticed that when I use ACC and am driving at night, the vehicle will apply the brakes when going down a hill to automatically match the required speed. I can actually see the side of the brake lights come on thru my side mirror. So yes the Jeep brake lights will come on with no actual pressing of the brake pedal in that instance. Not sure if that helps the OP for his situation...?
 
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jdegrave

jdegrave

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I have noticed that when I use ACC and am driving at night, the vehicle will apply the brakes when going down a hill to automatically match the required speed. I can actually see the side of the brake lights come on thru my side mirror. So yes the Jeep brake lights will come on with no actual pressing of the brake pedal in that instance. Not sure if that helps the OP for his situation...?
Very helpful! My son has a GoPro so I may borrow it and experiment with the ACC by following someone I know and having them adjust their speed accordingly. There are many times when it slows down fairly quickly and I have a hard time believing this is engine braking 100% of the time...
 

NickL

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Just received this response from Jeep Cares (I really appreciate the prompt response from the FCA team):

"Thank you for contacting Jeep Customer Care.

The Adaptive Cruise Control System adjusts speed slowly and gradually, (as if you are stepping off the gas). In a sense, the engine is downshifting. So is this respect, when the brake switch is not being activated (which is only achieved by applying the brake pedal), the brake lights will not come on.

The Forward Collision System is different, however. When this system engages, the brakes are electronically applied and therefore, the brake lights will illuminate.


Thank you,


J. Sanders
Fiat Chrysler Automobiles (FCA)
Mopar Headquarters"


So, according to this e-mail, at NO TIME should the ACC trip the brake lights since it only slows the vehicle down and doesn't use the brakes at all. If any of the Jeep Cares folks are here please confirm my understanding (or any of my fellow Jeepers for that matter).
When the ACC on mine actually brakes, the brake lights do come on. When letting off the gas by ACC they do not come on. Much the same as when driving without ACC.
 

cjaama

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I already knew this, but as of this morning I can say with absolute certainty that the brake lights come on when the ACC system uses brakes. I had an inch of snow on top of my spare tire this morning and could see the third brake light coming on and off.
OP got a bull shit answer from someone at Jeep that didn't understand the question or what the answer was.
 

Karl_in_Chicago

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I already knew this, but as of this morning I can say with absolute certainty that the brake lights come on when the ACC system uses brakes. I had an inch of snow on top of my spare tire this morning and could see the third brake light coming on and off.
OP got a bull shit answer from someone at Jeep that didn't understand the question or what the answer was.
Except nobody in this thread (at least from what I recall) was stating that the brake lights don't come on when the brakes are applied. The OP's question was whether brake lights come on when other, non-brake, methods are being used to slow the car (consensus was they don't, which is how pretty much all other vehicles that don't have ACC systems work as well). So I'm not sure what your point is.
 
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