Disconnect both battery terminals and wait 15 minutes for the airbag system to become safe before you do any work on the steering column or airbag parts.
The little fill in plates where the switches go should come right off and your answer will be underneath. The steering wheel should be set up with a place for the switches.
Post a picture of your steering wheel.
There have been some threads that claim the 1997 cruise control switches are different than the 99-01. I don't know what the 98 switches are like, 97 vs. 99.
If you already have the correct airbag in the steering wheel, than you just disconnect the parts needed ( Installing factory Cruise control questions - NAXJA Forums -::- North American XJ Association
) and install them on your Cherokee. Take notes or cell phone pics at the junkyard when you are getting your parts.