Shops rarely fail to find a part. They find the wrong one, order it, wait for it, try to fit it, and send it back. Getting it right starts with reading the car — and a car is covered in numbers, only one of which is the VIN.
Read the numbers
Fill in whatever you have. Nothing is required.
A VIN does not describe a car
A real 2013 F-150 decodes to 154 fields, of which 34 are populated. Trim, series, engine model, brake system description and axle configuration all come back empty. That is not a data-quality problem — a VIN is 17 characters and the regulation spends them elsewhere. Build date, option codes, trailering, axle ratio, suspension tune and cooling package were never encoded at all, and every one of them changes which part fits.
The rest of it
These decoders are the front of a shop tool that also scans the VIN barcode off the door-jamb label with a phone camera, records what a technician confirms about a vehicle, and learns which parts actually fit — a part earns a rule the first time it is confirmed and loses ground when it is not. That half needs a database, so it runs in the shop rather than here.