There are 3 cruise systems used on the vast majority of Fords:
1) Vacuum servo, used until the early 90s (its primary sensor is on the speedo cable and produces 6 pulses per cable rev);
2) Electronic servo, used ~'90~04 (primary sensor is the ABS system's wheel or differential sensors @ 54 or 108 pulses per wheel rev);
3) Integral (inside the PCM), used from ~'04-now on vehicles with an electric throttle (drive-by-wire).
All Fords use the same resistance on the cruise buttons, regardless of the cruise system they control. So any Ford steering wheel will work with any cruise. And it's easy to build your own buttons and mount them anywhere you like to control any Ford cruise, just by mimicking the resistance of the factory buttons.
This diagram shows the resistances, and its caption contains the pinout for the electronic servo:
This is the Ford troubleshooting guide for the vacuum servo system:
All current Ford PCMs are built with cruise, but on vehicles without that option (de-contented), a steering wheel without buttons is installed, and the PCM is programmed to disable the system. To add cruise to those vehicles, the steering wheel is swapped for one with buttons, and the PCM is reprogrammed to enable cruise. Of course, this integral system can't be added to an older vehicle without swapping in the modern PCM, the engine with electric throttle, the modern transmission with shaft sensors, and much of the wiring harness.
If you're talking about using the electronic servo system, then there's nothing in the EEC to flash - the cruise system resides entirely within the servo, and does not rely on the EEC/PCM for anything.
I put the vacuum system on a '75 Bronco because I did an EFI swap to it, and the donor was an '88 F150 XLT, so I just used its cruise. It worked perfectly for over a decade, and probably still does for its new owner.
But the electronic & integral systems are significantly better in many ways. The most-apparent (and probably least-known) is that they respond to the buttons by exactly 1 MPH per button press (a feature exclusive to Ford cruise).
Most wiring diagrams for most vehicles can be found here:
http://www.revbase.com/BBBMotor/Wd
