A system and method for determining that a male terminal and a female terminal are becoming disconnected in a connector as a result of the connector becoming loose or the terminals becoming corroded. The connector is a multi-terminal connector including a male terminal housing that houses a plurality of male terminals and a female terminal housing that houses a plurality of associated female terminals. One of the male terminals is a diagnostic terminal that is shorter than the other male terminals so that it is disconnected from its associated female terminal before the other male terminals when the terminal housing separate, which can be used to detect connector failure.