Western Star Bodybuilder Book: Revision 3.2a 1A J1939 Connection P. 1A-23 b The J1939 Datalink EOL connections T.o.C. located behind dash panel (NON-MAN) ABS ECC TRANS ICU ENG 120 Ohm (Option driven Terminating Gateway Resistor by 835-003) 835-998 uses 120 Ohm Backbone RADAR RADAR MGW DIAG Branch terminating DISPLAY (Cummins Only) Circuit resistor (Option driven by 736-1AF) Optional 250K WST J1939 System Connections Diagnostic Connector (Driven by 160-039) J1939 Connections Tying into the J1939 backbone is accomplished by tapping into the system using the terminating resistor tee’s located at each end of the backbone.
Terminating Resistor on J1939 500K 2016 and newer units have a new 500K J1939 interface for the diagnostic plug and main engine/transmission signals. Backbone A 250KB gateway is provided for connecting to the system, the optional secondary diagnostic plug to access the 250K network, is located at the center of the dash console beneath the switch panel. 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 resistors that are missing or disconnected. Ÿ If connections under dash become disconnected:
Ÿ All J1939 500K circuits will be green/white striped and yellow/white striped wires. Ÿ All J1939 250K circuits will be solid green and solid yellow wires. Ÿ 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 End of Line (EOL) Connections (Image referencing Cummins EOL) Models: 4700 ENH Models: 4700 ENH MGW (Cummins Only)