There are 2 fuses in the rear fuse block that supplies power to the relays for the fuel door lock solenoid. The ALDL fuse, and the body fuse. You can start by checking those, but I'd expect other problems if they were blown. The schematics show 2 relays, one for locking the other for releasing in the rear fuse block, but I couldn't find those specific ones listed in the diagram for the rear fuse block. They could possibly be relays 47 & 50. F/trnkdr lock and rel relays.
However, I would suggest lubing the mechanism first to see if that helps. It can easily be removed from the outside, after opening the fuel door.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.