The door locks could be a fuse problem but I doubt the seat belts are fuses individually.
See Figure 1
The fuse panel is located below and to the left of the steering column.
Fuses are a one-time circuit protection. If a circuit is overloaded or shorts, the fuse will blow thus protecting the circuit. A fuse will continue to blow until the circuit is repaired.
Fig. 1: Main fuse box located on driver's side to the left of the steering wheel, above the brake pedal