I have a niner like yours. Mine was a dirty contact in the switch. This is what fixed it for me:
Spray behind all the cruise switches with electrical contact cleaner, then work the heck out of em. Repeat two or three times. Allow to dry for several hours before powering up.
If you don't think that's it, break out the multimeter and start trouble shooting
March 2014 GCOTM. 1998 Deep Slate 5.9
On the Jeep:Hot intake, 52mm TB, Summit 8mm wires, catch can, 703s, insulated fuel rails, indexed Champions, Bilstein 4600s, Eibach lowering springs, Moog SS, Ironman mounts, Lotek 2GP, lots of gauges, sparkly paint.
In the garage: M1 4bbl
In the works: Addco/Hellwig sway bars, nitrous, full polly bushings, full exhaust, data logging, billet UD pulleys