The Delphi Harsh Environment Series (HES) connection system includes circular connectors, contacts, and a J1939 diagnostic circular connector. The 24 shell size industry standard connector includes six terminal configurations (47, 31, 29, 23, 21, and 19) and is offered with and without backshells. Delphi’s circular connection systems are available with straight and right angle conduit wire dress covers on both receptacle and plug assemblies. The HES connection system provides higher current capability, improved sealing, higher terminal retention and a significant cost advantage compared to standard pin-and-sleeve systems. Also, Delphi HES is compatible with existing systems in the commercial and agricultural vehicle markets.