[PDF] Speciﬁcations - Wanderlodge Owners Group tronic Controls (DDEC) II wiring diagram. See Fig. 2 and Fig. 3 for partial (detailed) views of the full view of the DDEC II wiring diagram. See Fig. 4 for a full view of the DDEC III wiring diagram (the engine side). See Fig. 5 and Fig. 6 for partial (detailed) views of the full view of the DDEC III wiring diagram Detroit Diesel DDEC III and IV ECM Vehicle and Engine These are the pin numbers on the DDEC III and DDEC IV vehicle connector on your ECM. The vehicle harness plugs into this connector. This diagrams what you would see if you looked directly at the connector. Refer to the table below to map these pins to their wire number, color and function.