2002 was during the recall years for the deactivator switch and its harness so that's something to keep in mind.

If you haven't performed the speed control servo integrated self diagnostic test you should do that 1st because it may tell you the problem.

There's plenty of youtubes showing how to do it. Here's the drill:

1) Enter self-test diagnostics by firmly pressing and holding the speed control OFF switch while quickly cycling the ignition switch from
RUN-to-OFF-to-RUN, making sure the engine does not start and is not running.

2) The speed control indicator lamp on the instrument panel will flash once to indicate that the speed control module has entered the self test diagnostic mode. Release the switch. If 5 flashes are displayed at this point, a speed control subsystem concern exists. 

3) Then firmly press and release the remaining switches WITHIN 1 SECOND of each other in the sequence below. The speed control indicator lamp flashes once after each of the buttons is successfully pressed (steps 2 thru 5).

4) Also, within .25 seconds after the static test has completed, the speed control actuator carries out a dynamic pull test. The actuator automatically pulls the speed control cable .04 to .39″ (1 to 10 mm) to move the throttle from the idle position and then releases the speed control cable returning the throttle to the idle position. 

So pop the hood and watch for that to make sure there isn't a problem with something binding up.

If the tests starts and then stops or just doesn't start then it could be specific to that recall on the deactivator switch and its wiring on your 2002.

The recall was because brake fluid would leak through the Speed Control Deactivation Switch (SCDS) and sometimes wick up into the wiring which was either corroding the wires between the deactivator switch and the servo (which Ford would have never issued a recall for) or overheated the switch or wiring which started a fire (which forced Ford to issue the recall).

If the test won't run you want to unplug the connector to the SCDS and the one at the servo and inspect them for heat damage or brake fluid in their wiring connectors.

Then confirm that the recall repair was performed.

They added a jumper wire with a fuse in it so the original wiring harness could be connected to the replacement SCDS switch. (the fuse kept the truck for burning down because they had enough of those lawsuits).

Depending on Ford's replacement parts availability the recall harness either looked like the image on the Left with a non-serviceable fusible link inside the jumper or like the image on the Right that came with either a fusible link or a replaceable fuse.

But whichever, they both plugged into the original harness connector that went to the SCDS switch (Red arrows) and if the Self Test isn't running you can try unplugging the connector and using a paperclip jumping the 2 terminals on that connector and try running the test again. This connector:

(The SCDS switch is normally closed when the brake ISN'T being pressed. If the switch failed in the Open position ((when the brake was pressed)) or if the fuse in the jumper wire is blown the circuit will be Open and the cruise control won't work) Jumping that connector will Close the circuit and determine if the problem is in the jumper wire or the SCDS switch (which will be easy to determine by repeating the paperclip jump on the terminals of that jumper harness connector on the SCDS) .

No that's pretty much it enough to speedometer is working that part's working too

Update...........  the cruise control is now working. Replaced the Speed Control Deactivation Switch on the master cylinder and cruise works. Thanks jack62 for the help.

Thanks jack62. That's some great info. I'll give it a try.