When I first bought my 2000 wrangler the cruise didn't work. It would indicate it was on, but not engage. It was the steering wheel switch, easy fix. That system used 5 switches and only 2 wires, the computer read the resistance of each switch to know which one you pressed! This was an old style system, with a vacuum actuator and a cable throttle, but it still used the engine computer to function. Most of the tests I did to find the problem were voltage checks at the engine computer connectors.
If your vehicle is "drive by wire" (no physical cable between the accelerator pedal and the engine) then the cruise is all in the engine computer.
These things can always be fixed. I'm thinking the Ford Dealer is the best bet.