What does Auto Stop/Start have to do with towing a trailer????

[sirdude]

Hi All.....

Rarely post anything, but I have run into what I think is a very odd problem. I have a 2021 Bronco Badlands that I purchased new in September of 21'. I noticed that the ASS was only working intermittently and eventually stopped all together. I wasn't too worried about it because I only used it rarely. Bout a year go I went camping in the mountains of NC and I towed a tear drop trailer and I was using the seven pin connector so all the blind spot/parking sensors/cross traffic alert, etc. are all disabled. So when I got home and unhooked the trailer I noticed that the ASS was working again. It worked for about a week and then it started getting intermittent again and stopped altogether a sort time later. I figured it was a conscience. I went camping again last weekend, got home on Monday and of course the ASS is working again.

Can someone tell me what the hell one has got to do with the other (Towing a trailer making the ASS work for a while)???? The only explanation I can come up with that the battery is charging at a rate of 14.8V while driving for five hours on the interstate. And then that long coming home a few days later. The higher rate of charge may have raised the battery voltage enough so that the ASS doesn't think its too low to shut the engine off once in a while.?????

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[AK SNO RIDER]

I think you're on the right track. The BMS in Ford vehicles is incredible garbage and constantly disables systems, start/stop being one of those.

Battery voltage can be fine by if the system hasn't sensed what it considers to be enough charge vs discharge it will disable shit.

My zone lighting hasn't worked properly for a year because of this, even though my battery is fine.

 

[cbrenthus]

I don't know as much about the ASS in the Bronco, but I know that Stellantis vehicles measure the battery charge and make sure it is 100% charged before allowing ASS to work. If the Bronco is the same, it has nothing to do with towing, but rather you probably have a battery that isn't being charged 100% during normal daily driving, but got charged up after a long trip. Happened to my Wrangler a few times.

 

[HighVelocity]

Does your trailer have a house battery and a converter or DC to DC charger? If so, I'd imagine ASS is disabled while hooked up due to the trailer battery pulling a charge.

Electric trailer brakes would also pull power from the vehicle as well.

 

[sirdude]

I think you're on the right track. The BMS in Ford vehicles is incredible garbage and constantly disables systems, start/stop being one of those.

Battery voltage can be fine by if the system hasn't sensed what it considers to be enough charge vs discharge it will disable shit.

My zone lighting hasn't worked properly for a year because of this, even though my battery is fine.

I haven't had any problems with zone lighting or any other electrical problems. I would THINK that with 14.8 volts going back into the battery it would be sufficiently charged to operate all the systems as it was designed to do.....but I guess not. Actually, when I was a youngin, 14.8 would have been considered over charging, back then 13.8 was considered normal

 

[sirdude]

I don't know as much about the ASS in the Bronco, but I know that Stellantis vehicles measure the battery charge and make sure it is 100% charged before allowing ASS to work. If the Bronco is the same, it has nothing to do with towing, but rather you probably have a battery that isn't being charged 100% during normal daily driving, but got charged up after a long trip. Happened to my Wrangler a few times.

Yep......about the only thing I can figure....good think I dont NEED it....

 

[sirdude]

Does your trailer have a house battery and a converter or DC to DC charger? If so, I'd imagine ASS is disabled while hooked up due to the trailer battery pulling a charge.

Electric trailer brakes would also pull power from the vehicle as well.

You are correct, it does not work with the trailer hooked up and I suspect for the reasons you mentioned.

 

[AZ_Liberty]

AS/S is supposed to be disabled by plugging in a trailer. That was one of the tricks on the F-150 forum. You'd get a brake light that installed in your hitch that you plugged in. Truck automatically disabled AS/S.

 

[gwp]

Hi All.....

Rarely post anything, but I have run into what I think is a very odd problem. I have a 2021 Bronco Badlands that I purchased new in September of 21'. I noticed that the ASS was only working intermittently and eventually stopped all together. I wasn't too worried about it because I only used it rarely. Bout a year go I went camping in the mountains of NC and I towed a tear drop trailer and I was using the seven pin connector so all the blind spot/parking sensors/cross traffic alert, etc. are all disabled. So when I got home and unhooked the trailer I noticed that the ASS was working again. It worked for about a week and then it started getting intermittent again and stopped altogether a sort time later. I figured it was a conscience. I went camping again last weekend, got home on Monday and of course the ASS is working again.

Can someone tell me what the hell one has got to do with the other (Towing a trailer making the ASS work for a while)???? The only explanation I can come up with that the battery is charging at a rate of 14.8V while driving for five hours on the interstate. And then that long coming home a few days later. The higher rate of charge may have raised the battery voltage enough so that the ASS doesn't think its too low to shut the engine off once in a while.?????

My ASS does not work with the doors off….. after I take the doors ASS works for a day or two, and then quits. It also takes a couple of days to realize the doors are on again, before it decides to work. it’s a 7MT two door. Go figure…

 

[Mdozier]

AS/S is supposed to be disabled by plugging in a trailer. That was one of the tricks on the F-150 forum. You'd get a brake light that installed in your hitch that you plugged in. Truck automatically disabled AS/S.

This.
My dealer told me the trick of simply getting a cheap or old flat connector and cutting off the leads and plugging it in to disable the ASS. Sure enough, I found a flat connector and cut off the harness and plugged it in and it disabled the ASS as long as it was plugged in.

My guess, when you're towing (plugged in) you're disabling the ASS and that's doing some type of reset so when you unplug, it starts working again but there's some spurious intermittent electrical bug-a-boo that is causing it to start acting up after.

Just my guess.

 

[KABQ]

The 14.8V you are reading on the dash is the RATE of charge, not the STATE of charge. Basically the higher the number the lower your battery is. I've seen up to 15.2V on mine when it's cold. Gel batteries are weird, so I had to try to forget everything I know about lead-acid to not freak out at that number.

 

[sirdude]

The 14.8V you are reading on the dash is the RATE of charge, not the STATE of charge. Basically the higher the number the lower your battery is. I've seen up to 15.2V on mine when it's cold. Gel batteries are weird, so I had to try to forget everything I know about lead-acid to not freak out at that number.

I understsand it's the rate not the state, however I did NOT know that it was Gel battery....that makes a little more sense.

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