1) The new wire harness model should be consistent with the original model. The wire terminals and wires are connected reliably. You can pull the connectors and wires by hand to see if they are loose or fall off.
2) Compare the new wiring harness with the original wiring harness. For example, the size of the wiring harness, the wire terminal fittings, and the wire color should be basically the same. If there is any doubt, you can test it with a multimeter to confirm that the wire harness is intact before it can be replaced.