When one of my '97s wouldn't disarm with the key in the driver's door but would in the passenger door and hatch, I had to replace the driver's door disarm switch. I wasn't fortunate enough that it was only that the disarm switch had come loose from the lock cylinder. With the door panel off, you can reach up and snap the switch off of the rear of the lock cylinder and then unplug the 2-wire electrical connector. New disarm switch snaps right back onto the lock cylinder. Disarm switch was about $35 from the dealer.
96 4x4 Laredo, 97 4x4 Limited, 97 4x2 Limited