the wiring on your car cabin passes from "outside" the cabin frame near the door hinge area and reenters the engine room at the front corners, To protect the wiring and bodywork toyota installed plastic fender shields so the wiring does not get doused with water/mud/debris etc.
If they are missing all sorts of wiring nightmares will start.
The wiring circuit for the headlamps in your car is routed through a relay that is mounted near the accelerator pedal behind the plastic kick panel on the right.
If those wires are corrodded or muddy - there is no repair other than to completely make new wiring and also test the fuse box hanging on the battery frame.
The wiring on that car is even simpler than a mehran/fx . Find a good electrician/technician to repair it correctly (they wont be the cheap roadside guys)