I did a google search and came up with this:
http://wiki.answers.com/Q/Where_is_the_cigarette_lighter_fuse_located_on_a_97_Jeep_Wrangler'There is a relay next to a harnes underneath the glove box...regular manuals dont show this ... I checked on a dealership service manual and found the location '
I also found this, and I assume it is for a 98':
"Fuse 5 (under the hood) feeds power to the cigarette lighter/accessory relay, which is energized when the ignition key is in the ON or ACC position. The relay feeds power to Fuse 19 (behind the glove box) which powers the cigarette lighter itself and also the extra "Switched power" wire that early model TJs had tucked into the wiring harness behind the glove box."
I remember having to change my fuse when my portable air compressor would blow it. I just looked in my Jeep and there are 3 on the left side that run off the ignition. None are labeled, but that would be my guess.
MY 98' FSM mentions an accessory relay. It says, and I quote:
"The accessory relay is located in a wire harness connector that is secured to the 100-wa connector bracket under the drivers side of the instrument panel. near the cowl side inner panel in the passenger compartment. The accessory relay cannot be repaired and, if faulty or damaged, it must be replaced. "
I also am looking into the page 8W-15-7 of my Factory Service manual, and the Fog Lamp relay, left and right door ajar, wiper switch and motor, stop lamp , and cigar lighter accessory relay seem to go to Fuse 4. Then again I have no idea how to read a wireing diagram, so I would take this last paragraph of information with a grain of salt.
If you need a picture of the accessory relay, let me know and I can scan it and post it for you.
HTH,
Jeff