Improper Terminal Engagement Check
WARNING: This page is about a different car, the 2012 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.
Terminals inside a connector may not engage properly even if the connectors engage. Make sure that each terminal does not come out of the connector when gently pulling each harness wire. If it does, repair or replace the terminal and/or connector.