To clarify the instrument cluster swap from IDIOT lights to GAUGES....
It is a plug and play, BUT......
Since you have a 98 as your user name indicates... DO NOT get a instrument cluster from a 97 TJ or XJ.... I have the wiring schematics for a 97 and 98 XJ and there are differences.... The wiring in the 97 XJ is slightly different.... The ground wiring difference affects the built in timer for the rear window defroster and there is another pin location change that affects the windshield washer low level indicator... The defroster will not work and the low level indicator will stay on....
You can use an instrument cluster from a 98 or 99 TJ or a 98-01 XJ.
Charles