Consider your self lucky it doesn't work

 

Right. I bought one three years ago and works perfectly. But people is weird these days. They'll spend thousands on all kind of accessories for the trucks but find the Autostop Eliminator expensive. Go figure.

 

You are asking HOW the previous owner disabled ***, the short answer is there are multiple ways to disable ***. As I read your post, I don't think you intend to enable ***, but you simply want to understand how it was done. I'll post a link below that lists several methods. Since that link was published, there are more documented methods on this forum. However, this may give you a starting point as you are going to have to do some looking to figure out how it was disabled.

With regards to your question about towing, I'd look at the method which removes a wire from the Trailer Control Module. The trailer control module is located near the brake pedal, under the dash. This should be plugged in if you tow.

Good luck with determining how it was done.

Disable auto start/stop for good - Page 43 - Ford F150 Forum - Community of Ford Truck Fan

One can disable the BMS at the negative battery post, which is not in the list above. There is a small device on the negative battery post, and you'd find a disconnected wire....
I'd suggest looking at the back of the *** switch to see if they simply jumped (with a wire or paperclip) across the 2 pins in the switch.
I'd also look at the FORScan method. Do you have the ability in the menu to look at why *** is not working (is a menu option in the instrument cluster)? With the FORScan method, this menu item can be removed (if it is removed, might be a clue FORScan was used...) Note, with FORScan one does not have to remove the *** status from the menu, but can remove it if wanted... so again, it is just another clue as to what they might have done.

 

AFAIK, this method also disables the Battery Management System, that shuts off battery drain if power gets low.
IOW, the easy ways are not usually the better ways.
Disconnect the bottom wire from the trailer control module in the drivers footwell. A.S.S. module thinks a trailer is connected and is disabled. Unfortunately so are some towing functions.
Plug a 7 pin electrical tester into the hitch receiver jack. Again, fake trailer is detected. But it sticks out of the bumper by the tailgate.

The overpriced module & wiring harness was about $110. A little pricey when you can just push the disable button, BUT, you no longer have to do this EVERY TIME you start the truck. Worth the loss of aggravation to me.

If you are electrical savvy, the wire jumper method works great and leaves it off. But with the Auto StartStop Eliminator, I could enable the A.S.S. Not likely!

 

Forgot to add.
Do you have any indication of a trailer attached? You’d get that with most of those other methods.
Do you receive the dash warning, “Auto start stop disabled by operator”? Happens with the Eliminator.

I went on UTube and watched how to remove the center dash Bezel/trim. No a lot of space to jam in the Auto Stop Start module & wiring harness. You need to do that to add the jumper.
That knowledge was used again when I added the Hill Decent control switch when I enabled the feature using Forscan.

 

Toggle through the trucks diagnostics and find out if the *** is off because the battery is charging. Mine goes through periods where it doesn’t function because it says the battery is charging. Days at a time sometimes. I suspect that’s a function of how it’s driven over a period of time. Personally, while I sometimes notice the auto SS in action, it really doesn’t bother me. I let it do it’s thing unless I’m in traffic or a drive thru. My wife’s car doesn’t have it and I have found myself wondering briefly when it was going to shut off……