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Electrical Sysem 6-14 627333-A FIG. 6: CAN Harnesses 1. Stub Cabling 2. T-Connectors 3. Terminators 4. J1939 Backbone FIG. 7: Back Harness Connector Pin A to C should be 2.5 volts. Pin B to C should be 2.3 volts. Pin A to B should be 0.0 volts. 1. A - CAN High (yellow) 2. B - CAN low (green) 3. C - CAN shield (grey) I/O module connectors: J2 (gray) and J3 (black). CAN backbone Harness - Gray connectors are located under right rear corner of the cab - one for chassis and one for system. Connectors can be disconnected one at a time to isolate problems down to system or chassis. Check for CAN high and CAN low on these connectors. Check for power on pin D and ground pin E. Always check pins for moisture, corrosion and loose pins. Example: Once problem is isolated down to system or chassis, further testing can be done. • If problem is on system side, check furthermost end of system backbone harness - taillights. Disconnect cable going into tee connector. • If chassis starts working, problem has been isolated to taillight tee connector or cabling. • If problem still exists, taillight system has been eliminated. • Repeat procedure at next tee connector forward until problem is found. Must do a battery disconnect every time when plugging or unplugging CAN network. FIG. 8: Chassis CAN Bus Power Connector FIG. 6 Q000088S 3 2 4 1 FIG. 7 Q000089S 3 2 1 FIG. 8 Q000090S 1 5 4 3 2 CAN BUS POWER CONNECTOR CAV CABLE END COLOR CABLE TAG A (1) 1A YEL 1290 B (2) 2A GRN 1291 C (3) 3A GRA/BLK 1292 D (4) 8A RED 392 E (5) 9A GRA 397 |