it sounds like someone took it out, or the car came factory with a single cd in dash unit, and someone swapped the radio with a cassette, seen it a million times. the 98's came different ways as far as where the changer was, some have them where they always were, left rear corner, or under the package tray, they also came factory with a 10 disc or a thinner smaller 6 disc. look around the trunk under the rug and see if you can find the stock changer harness, most likely it is on the left side behind the air suspension switch door, see if someone tucked it back there. if it is there, start looking for a used unit, you'll find one. or you can keep everything you have now, and just go with an FM modulated changer like the pioneer one i have in my 93, stock jbl system, with a pioneer 10 disc changer in the trunk still, some people dont like FM modulated changers but mine sounds like any other one i have ever heard.