How do you fix truck tailgate that won't close?

To fix a truck tailgate that won't close, first inspect the hinges and latches for any visible damage or debris. Ensure the tailgate is properly aligned with the truck bed; if it's misaligned, adjust it as needed. Check the latch mechanism for obstructions or rust, lubricating it if necessary. If these steps don't resolve the issue, consider replacing any damaged components or consulting a professional for further assistance.