Ford warns that Active Cruise Control can NOT be used with an aftermarket trailer brake controller

[TechnicallyReal]

I had checked with Tekonsha several years ago when installing a P3 and I was told by their tech department that hard deceleration (even downshifts) would activate the trailer brakes due to the pendulum movement.
I checked the owners manual for that P3 just now and it was still a bit vague on the subject.
So I called Tekonsha once again to confirm and got electronic telephone run around.

Upon reflection however, I believe you are right and I was misinformed.
My Bad
(I have deleted that post)

I appreciate that you double-checked this and reported back. You're a bigger man than most. It's interesting, though, because if their brake controller did activate in such a way then it would change the conversation for sure.

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[Floyd]

here's a question which may put this discussion back on track...
Reading post #1 again, why is the admonition only in conjunction with the use of
Adaptive Cruise Control ?

 

[TechnicallyReal]

here's a question which may put this discussion back on track...
Reading post #1 again, why is the admonition only in conjunction with the use of
Adaptive Cruise Control ?

It's just mentioned in the manual under ACC. I don't think Ford made a big announcement about it (I could be wrong).

Hilariously AEB isn't even mentioned in the manual at all last time I searched it. I also tried searching for the full name but came up empty.

 

[VAMike]

if their brake controller did activate in such a way then it would change the conversation for sure.

I think what would happen is that the trailer brakes would come on whenever you slow down (e.g., take your foot off the gas pedal) and wouldn't turn off until you hit the gas hard enough to start accelerating again (with the trailer brakes applied) or until you stop completely. Definitely a conversation starter.

 

[Silverfox]

Should be relatively easy to test. Get up to speed and hold a gear at highish rpm. Let off the gas with the gain set to max. Then try again with gain set to minimum. You should feel a difference if it does in fact engage the trailer brakes without pedal input.

 

[t4thfavor]

Should be relatively easy to test. Get up to speed and hold a gear at highish rpm. Let off the gas with the gain set to max. Then try again with gain set to minimum. You should feel a difference if it does in fact engage the trailer brakes without pedal input.

You’d be able to see the screen on the p3 changing numbers. I’ve had a p3 installed since 2019 and it’s perfectly fine. However I do believe it could cause trouble should the brakes come on full force to avoid a crash. Someone said earlier that Ford should be providing the minimum hardware required or at least providing the standard wires at no cost. If they would sell the little ecm module, or had included it from the factory, we wouldn’t be here.

As long as you were paying some attention as soon as you touch the brake pedal, the p3 will supply exactly the right amount of brakes regardless of your pedal input.

 

[Floyd]

Still, nobody, to my knowledge, not even Ford, has made an exclusive link between Adaptive Cruise Control and the prohibition of its use while towing with an aftermarket Brake Controller.
1] There is no actual OEM Ford brake controller.(a technicality I admit)
2]The one which Ford offers to install aftermarket is a Ford approved aftermarket controller with a fix.
3] Unless Adaptive Cruise Control allows for apparent Tailgating, then the culprit would logically be the AEB in specific or cruise control in general.
4]As quoted above, directly from the Ford Ranger Owner's Manual ( see post #162) It is Ford's contention that it is the driver's responsibility to pay attention and apply the brakes when needed..

Bottom line is to slow down, pay attention, and increase following distances when Towing, even
(or especially) when the trailer has no brakes.

Certainly any activation of AEB would disengage the Cruise Control, Adaptive or not.

There has always been a faction in the towing community which says that you should never use cruise control at all when towing...
I am not one of them, but like any tool or feature...you should learn to use it responsibly.

Without further explanation one could only conclude that this admonition is nothing more than just another CYA attempt on the part Ford corporate lawyers running around with their hair on fire.

Just askin'

 

[WOADKIL]

I have been using ACC and AEB for months with my 4,000 trailer. Works great with th Redarc brake controller.

With or without brake controllers, the driver's actions/method of driving should be abso-4ucking-lutely NO DIFFERENT!

As the Doors would say:

Yeah, keep your eyes on the road, your hand upon the wheel
Keep your eyes on the road, your hands upon the wheel
Yeah, we're goin' to the Roadhouse
We're gonna have a real Good time

Alls I'm saying...

Be safe!

 

[VAMike]

There's just no point in continuing to speculate about what the warning means. There's been no new information from ford in the past 2 years, and we're unlikely to see any clarification. Rehashing old discussions and making assertions with no way to validate what's true doesn't add any light to the situation.

 

[awd.nv]

I figure I would comment and mention I have towed about 2k miles now and use adaptive cruise quite often. I have had no issues with the Curt Spectrum brake controller and ACC. I tow a 19ft 4000lb travel trailer (Geo Pro 19BH)

I primarily use adaptive cruise control on open highways or to match the speed of the cars in front of me in open hwy environment. If traffic starts slowing down I switch to manual. I would not use it in the city while towing personally so who knows how it would work there with the trailer brakes.

I have had zero issues. Maybe it is a cover your behind from Ford should the brake controller apply brakes or not apply them properly if ACC does any decent brake input?

Just sharing my experience.

 

[TechnicallyReal]

I've spent a lot of time researching and digging into this (I had a really hard time accepting that Ford's TBC was the only one we should use, since I already had a different one I wanted to use instead). I've only been chiming in about AEB but the same concerns apply to ACC as well.

Put simply, if your brake controller uses the brake pedal signal (the wire under the dash) instead of the brake light signal (such as the one sent to the CHMSL), then your brake controller won't activate your trailer brakes when the Ranger brakes itself automatically via AEB or ACC. The brake controller just doesn't get the memo that the vehicle is braking and that it should do something.

Is it obvious if your brake controller isn't working with AEB or AAC? No. Not until AEB or ACC tries to brake hard enough that you would need the assistance of trailer brakes. For light braking, the Ranger's brakes are usually more than enough. This is what makes it scary, though. It's not a problem until it's a problem.

This reason the wire under the dash doesn't send a signal when AEB or ACC apply the brakes is presumably because of a screwup by Ford, who appear to have slapped AEB and ACC onto the Ranger without updating the wiring below the dash to work with it (keep in mind the Ranger existed overseas without AEB or ACC before coming to North America).

The reason aftermarket brake controllers can't detect AEB / ACC braking by themselves seems to be because the vehicle is the only "source of truth" as to whether or not the brakes are really being applied. There's no reason for a brake controller to make guesses when the vehicle can simply tell it with confidence (with the correct wiring). All of the aftermarket brake controllers I've looked at or seen mentioned on this forum work this way. Think yours works differently? You can actually test it yourself (but I won't get into how in this post).

The reason Ford's OEM brake controller works with AEB / ACC is because they've included a Lumen-branded module to compliment the RedArc TBC in their OEM kit. The Lumen module taps into the brake light signals at the CHMSL and transforms them into a simpler signal like the one used on the brake pedal wire. A single wire from the Lumen module is connected to the brake controller, instead of the brake pedal wire under the dash. When AEB or ACC apply the vehicle brakes, the brake lights turn on, and the Lumen module gives word to the brake controller that it should do something.

Ford could sell the Lumen module for use with any aftermarket brake controller if they wanted to. It might be possible to source them elsewhere, but I don't know where.

Aftermarket brake controllers aren't as smart or complicated as people think they are. Aside from a dumb on/off brake signal that is fed into them, they don't get any other data from the vehicle about what's going on or what to do. There are exceptions such as with integrated brake controllers but that's another story. Instead, they just sit idly by until they are told that the truck is braking. They purposely do not try to figure out when the truck is braking on their own, as that would complicate matters and introduce false positives (unexpected trailer braking from bumps, gear shifts, speed bumps, potholes, shift in load, etc). Instead they rely on a dumb on/off signal from the vehicle before applying the trailer brakes. Once they are told that the truck is braking (and not before then), they use their various sensors to determine how hard the truck is braking and activate the trailer brakes proportionately. Since the vehicle isn't feeding them data on how hard to brake, they have to figure that part out entirely on their own.

 

[Floyd]

I've spent a lot of time researching and digging into this (I had a really hard time accepting that Ford's TBC was the only one we should use, since I already had a different one I wanted to use instead). I've only been chiming in about AEB but the same concerns apply to ACC as well.

Put simply, if your brake controller uses the brake pedal signal (the wire under the dash) instead of the brake light signal (such as the one sent to the CHMSL), then your brake controller won't activate your trailer brakes when the Ranger brakes itself automatically via AEB or ACC. The brake controller just doesn't get the memo that the vehicle is braking and that it should do something.

Is it obvious if your brake controller isn't working with AEB or AAC? No. Not until AEB or ACC tries to brake hard enough that you would need the assistance of trailer brakes. For light braking, the Ranger's brakes are usually more than enough. This is what makes it scary, though. It's not a problem until it's a problem.

This reason the wire under the dash doesn't send a signal when AEB or ACC apply the brakes is presumably because of a screwup by Ford, who appear to have slapped AEB and ACC onto the Ranger without updating the wiring below the dash to work with it (keep in mind the Ranger existed overseas without AEB or ACC before coming to North America).

The reason aftermarket brake controllers can't detect AEB / ACC braking by themselves seems to be because the vehicle is the only "source of truth" as to whether or not the brakes are really being applied. There's really no reason for a brake controller to make guesses when the vehicle (with the correct wiring) can simply tell it with confidence. All of the aftermarket brake controllers I've looked at or seen mentioned on this forum work this way. Think yours works differently? You can test it yourself (I won't get into that in this post, though).

The reason Ford's OEM brake controller works with AEB / ACC is because they've included a Lumen-branded module in their OEM kit, which taps into the brake light signals sent to the CHMSL and transforms them into a simple signal like to the one used on the brake pedal wire, compatible with a brake controller. A single wire from the Lumen model is connected to the brake controller instead of the brake pedal wire under the dash. When AEB or ACC apply the vehicle brakes, the brake lights turn on, and the Lumen module gives word to the brake controller that it should do something.

Ford could sell the Lumen module for use with any aftermarket brake controller if they wanted to. It might be possible to source them elsewhere, but I don't know where.

Aftermarket brake controllers aren't as smart or complicated as people think they are. Aside from a dumb on/off brake signal that is fed into them, they don't get any other data from the vehicle about what's going on or what to do. There are exceptions such as with integrated brake controllers but that's another story. Instead, they just sit idly by until they are told that the truck is braking. They purposely do not try to figure out when the truck is braking on their own, as that would complicate matters and introduce false positives (unexpected trailer braking from bumps, gear shifts, speed bumps, potholes, shift in load, etc). Instead they rely on a dumb on/off signal from the vehicle before applying the trailer brakes. Once they are told that the truck is braking (and not before then), they use their various sensors to determine how hard the truck is braking and activate the trailer brakes proportionately. Since the vehicle isn't feeding them data on how hard to brake, they have to figure it out entirely on their own.

You have made what appears to be a very comprehensive explanation, but it begs the question at hand, which really is...
Why does the admonition apply to Adaptive Cruise Control only?
Standard Cruise Control is apparently not affected ???

There are any number of reasonable explanations, it is true that Standard Cruise control requires proper attention to traffic ahead whereas Adaptive... not so much? At any rate, Ford clearly considers AEB to be a somewhat ineffective Bandaid for just that problem.

Perhaps the warning should be to not lean on a system (AEB) which is designed to be deployed only after an emergency has ....well, uhh Emerged!

I think most of us clearly understand the practical function of these systems and their limitations.
Personally, I like having AEB as a backup for a momentary lapse of attention, even though I have never needed it in fifty plus years of driving so far, and mine on my Ranger has never activated unintentionally in the 2-1/2 years I have owned it so far.

Perhaps this whole issue is pretty much a "Tempest in a Teacup" (NO, not a Pontiac)

 

[TechnicallyReal]

So you have made what appears to be a very comprehensive explanation, but it begs the question at hand, which really is...
Why does the admonition apply to Adaptive Cruise Control only?
Standard Cruise Control is apparently not affected ???

There are any number of reasonable explanations, it is true that Standard Cruise control requires proper attention to traffic ahead whereas Adaptive... not so much? At any rate, Ford clearly considers AEB to be a somewhat ineffective Bandaid for the just that problem.

Perhaps the warning should be to not lean on a system (AEB) which is designed to be deployed only after an emergency has ....well, uhh Emerged!

I think most of us clearly understand the practical function of these systems and their limitations.
Personally, I like having AEB as a backup for a momentary lapse of attention, even though I have never needed it in fifty plus years of driving so far, and mine on my Ranger has never activated unintentionally in the 2-1/2 years I have owned it so far.

Perhaps this whole issue is pretty much a "Tempest in a Teacup" (NO, not a Pontiac)

It only applies to adaptive cruise because standard cruise doesn't automatically activate the brakes for you.

 

[Floyd]

It only applies to adaptive cruise because standard cruise doesn't automatically activate the brakes for you...

Good point
I assume you mean that the Adaptive Cruise Control uses the brakes to enhance deceleration for maintaining the set following distance, which should normally be a mild application of the brakes.
AEB activation then becomes a question not directly related to the concern posed by Adaptive Cruise Control.
That seems plausible and is the best explanation I've heard.
So... we should view Ford's concern in this case, was not so much to avoid collision as with AEB, but rather to more efficiently maintain a safe following distance and avoid any possible trailer "push" which could cause a less than optimal function of the system... and possibly result in an accident or at least in the subsequent activation of AEB.

After all these pages, your single sentence has been the key to clearing the whole question.
(at least for me)
Thank You!

 

[TechnicallyReal]

AEB DOES, and that's the whole point.

Well, the manual doesn't even mention that AEB even exists in the first place, so I guess that also means that there isn't a section to attach the warning to...

I think it's that simple.. and if you browse here enough you'll see no shortage of complaints about the manual being crappy lol

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