Western Star Bodybuilder Book: Revision 3.2a 1A J1939 Connection P. 1A-22 b The J1939 Datalink T.o.C. ABS TRANS ICU ENG 120 Ohm 120 Ohm Terminating Terminating Cab resistor Resistor Resistor located in dash 10” back from frontwall engine connection RXM DIAG Branch Backbone Circuit WST J1939 System Connections J1939 Connections Tying into the J1939 backbone is accomplished by tapping into the system resistor tee’s located at each end of the backbone. Front Wall The Chassis terminating resistor is located in a tee along the left frame rail, usually behind the cab.
Engine connection 40 pin 48/49/6900 The cab terminating resistor is located in the dash tapped 10” back from the Front Wall engine plug harness 76 pin 4700 Under the dash (shown on the left). The correct datalink resistance measured at any device, or at the diagnostic plug should be 60 Ohms with the battery disconnected. 2015 and older Western Star units have a 250KB data rate interface at both the diagnostic plug and the center tie in points. 2016 and newer units have a new 500K J1939 interface for the diagnostic plug and main engine/transmission Resistor Receptacle Signals.
A 250KB gateway is provided for connecting to the system and is located at the center of the dash Part FTL# 23-13303-902 console near the RH side of the steering column. Deutsch # DTM04 - 2P - EP10 IMPORTANT: Ÿ It is essential that both terminating resistors remain connected to the ends of the J1939 backbone to dampen feedback signals. Numerous J1939 problems can be attributed to terminated that are missing or disconnected. Ÿ If connections under dash become disconnected, connections should never be reconnected back together directly e.g., ABS with ABS as this creates an independent circuit in the system that is not connected to the backbone.
J1939 Connections for Body Builders To connect easily to J1939 at dash location order the following parts: (1) Tee and Jumper FTL# A06-37868-000 (1) Jumper Plug # DUFDTM06 2S E004 (2) Female Pins DUFWM2SB Models: 4700L/4800/4900/6900 Models: 4700L/4800/4900/6900