I had the same problem with my 98, turned out to just be a bad battery. Replaced the battery, and tightened the cables down all the way very tight, and it did the trick. To stay cheap, try to just undo both battery cables, and stretch the arms out wide, and clamp them back down as far as they can go, as the posts are tapered, and while holding the cable down tight, retighten the bolts. If that doesn't work...Well it may be time for a new battery too. But also try checking the door hatch light, take it off and check to be sure the plug is in tight, and there isn't any bad wires. If all the wiring is fine and tight, and all the door latch buttons are functional, and the battery cables are tight, like I said, you'll probably be needing a new battery.
'98 ZJ Laredo, 4.0L, 140K, NP242, stock. (Sold @205k)
'99 WJ Laredo, 4.7L, 175K, NP249, stock. (Sold @240k)
'97 ZJ Limited, 4.0L, 109K, NP249, stock.(Current)