This generation of full-sized Fords was a bit notorious for body computer problems that have symptoms very much like the ones you’ve listed. Essentially, the body computer is responsible for all the communication between the car’s various systems, including air-conditioning, cruise-control, central locking and much, much more. If the computer fails, replacement is usually the only real fix. Sometimes you’ll need to have the ignition key re-coded to the new computer, as well. The price quoted sounds about par for the course form what I’ve heard.

I’m with you that a car that’s only five years old probably shouldn’t need new components like a body computer, but when your car was brand-new, it was covered only by a three-year factory warranty. Ford Australia extended its warranty to five years in 2018 (for cars sold after that date) but that’s of little use to you. Twisting the dealer’s arm probably won’t do much, but have you contacted Ford Australia’s customer service division and stated your case? It might be worth your while.

It’s relatively widespread, Steve. In fact, it was enough of a problem for a while there that Ford was actually repairing some cars that were out of warranty. So that would be the first step: Tackle your local Ford dealer and ask the tough questions. A vehicle made in 2015 is too young to be rusty through bad design, but bear in mind that the dealer may not want to know and playing hardball on your part could result in legal costs if you follow it right through. And there’s no guarantee you’d win anyway.

There are shortcuts to rust repairs, but they all guarantee that the problem will recur. Fixing rust permanently requires removing all the affected metal, welding in new metal and rust-proofing the end result before repainting.

Somehow, moisture was able to enter the skin of the Territory’s tailgate and sit there and, naturally, rust was the end result. The area at the rear of the car around the tail-lights is also susceptible to corrosion. It’s interesting that the Territory had a storage space beneath the boot floor that was designed to accommodate wet bathers and wetsuits after a trip to the beach. Could this be the clue?

The three cars you name all have merit, none has any major issue to be concerned about and all fit your needs, but you will have to shop around to find them within your age and budget limits.