I don't recall, if I ever even knew, the bulb differences between '96 and '98, but IIRC on my '98 there is just an illumination bulb that comes on with the rest of the interior instrument/controls lights (window, lock, defog buttons, etc), not that lights or shuts off any bulbs based on which drive mode it's in.
In that case you could DIY (find a place to put it, panel mount) add a bulb or LED to light up when the 4WD clutch is energized by wiring that bulb or LED between the infamous brown wire and ground. Any low wattage 12V bulb would work but an LED would also need a series current limiting resistor, unless it was some type of ready-made automotive indicator assembly that already had a resistor built in. As far as that goes, in theory you could similarly rewire the existing illumination bulb for the drive mode selector switch to only come on with the 4WD clutch power but it seems counter-productive to not be able to see the switch at night when it's not on yet?
