SFN-20231016D_Replace the ABS circuit with a resettable circuit breaker

TICO Document #: SFN-20231016D (formerly TES-237)

Complication: An electrical short/fault in the trailer’s wiring is generating a current that exceeds the rated current of the 30A fuse and 30A circuit breaker. The trailer ABS fuse frequently trips and must be replaced each time a trip occurs. This is time consuming, as the it is not easily accessible.

Solution: Remove the existing trailer ABS circuit and replace it with a resettable circuit breaker that is easily accessible and can visually indicate to the driver when it has tripped.

Units Affected: UPS trucks with new cab style

Parts Required: KIT-TRAILER ABS, RESETTABLE CIRCUIT BREAKER 970039 (QTY) 1

Instructions:

1. Park the vehicle on a flat surface, apply the parking brake, and chock wheels. If your company utilizes a “Lock Out, Tag Out” policy, you should employ it during this procedure.

   Warning: To avoid electrical shock and/or damage to equipment, disconnect the battery cable from the negative side of the battery.

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2. Remove (4) bolts, nuts, and (8) washers on the cab step grate with a 9/16” socket wrench and 9/16” wrench. The wrench is used to hold the nuts below the grate in place. Retain the hardware. See Figure 3a.

3. Remove (4) bolts and (4) fender washers on the transmission grate with a 9/16” socket wrench. Retain the hardware. See Figure 3b.

4. Remove (8) bolts and washers on the chassis PDC box with a 7/16” socket wrench. Retain the hardware. See Figures 4a and 4b.

5. Locate the trailer ABS harness 2-pin connector. See Figures 5a and 5b.

6. Remove enough cable ties to free the ABS connector from the wire harness bundle, see, Figure 5b.

   Note: Multiple harnesses are routed underneath the PDC box and are secured altogether with cable ties. Several of these cable ties need to be removed in order to free the ABS connector. New cable ties are provided in the kit and will be installed later in the procedure.

7. Remove the 2-pin retaining clip and connector cap from the connector. See Figure 6a.

8. Remove both the blue and white wire from the connector. See Figure 6b.

   (Note: 2-pin connector, retaining clip, and cap can be discarded.)

9. Remove the convolute tubing and electrical tape on both wires. See Figure 6c.

10. Remove the cap from the conduit coupling by twisting it counterclockwise. See Figure 7a.

11. Lower both the cap and the rubber grommet inside the cap. See Figure 7b.

12. Pull both wires through the cap. See Figures 7c and 7d.

13. Pull each wire through the rubber grommet. See Figures 7e and 7f.

    Note: To avoid damaging the grommet, only pull one wire through it at a time.

    

14. Remove the fuse holder cover and 30A fuse from the fuse holder and discard it. See Figures 8a and 8b.

15. Press the fuse holder clip to release it from the mounting bracket and turn it over to the bottom side. See Figure 8b.

16. Remove the pin retaining clip. See Figure 8c.

17. Remove both the ABS ignition (yellow) wire and trailer ABS (blue) wire from the fuse holder. See Figures 8d and 8e.

18. Re-install the pin retaining clip and turn the fuse holder back over. See Figure 9a.

19. Re-mount the fuse holder back onto its mounting bracket, see Figure 9b.

20. Re-install the fuse holder cover, see Figure 9c.

    

21. Disconnect the ABS ignition wire from the starter solenoid using a 1/2” wrench, then remove the wire from PDC box. Discard the ABS ignition wire. Retain all hardware. See Figure 10a.

22. Remove the (2) cable ties that secure the convolute tubing on the inside wall of the PDC box. See Figure 10b.

23. Remove the electrical tape on both ends of the wire bundle, See Figure 10c.

24. Disconnect the ABS ground wire that is connected to the grounding busbar using a 7/16” wrench. Discard the ABS ground wire. Re-install the nut back onto the ground busbar and torque to 72- 96 in-lb. See Figure 10d.

25. Apply electrical tape and convolute to wire the bundle and secure it back to the PDC side wall with (2) cable ties that are included in the kit. See Figure 10e.

Note: There should be (7) components that have been removed and discarded. See Figure 11a for items #1-6 and Figure 11b for item #7.

• ABS ignition wire (Yellow)

• Trailer ABS wire (Blue)

• ABS ground wire (White)

• 2-pin connector

• 2-pin connector cap

• 2 pin connector retaining clip

• 30A fuse

26. Route the new ABS ignition wire through the conduit cap and then through the rubber grommet. See Figure 12a.

27. Route the wire into the PDC Box, then down along the inside wall next to the convolute tubing.

28. Connect the 5/16” ring terminal to the leftmost terminal on the starter solenoid and torque the nut to 60 in-lb. See Figure 12b.

29. Install (2) cable ties that are provided in this kit to secure the ABS ignition wire onto the convolute tubing. See Figure 12c.

30. Adjust the (2) harnesses now exiting the conduit coupling slightly upward so that there is no exposed wires, and then hand tighten the conduit cap clockwise until the harnesses are unable to move up and down, see Figure 12d.

31. Remove the lower (2) bolts, washers, and nuts from the trailer box mounting bracket that’s located on the protection bar using a 1/2” socket wrench and 1/2” wrench. Retain the hardware. See Figure 13a.

32. Mount the circuit breaker mounting bracket onto the back side of the trailer box bracket, then re-install the hardware and torque to 108 in-lb. See Figure 13b.

33. Secure the new circuit breaker harness onto the trailer lights harness with cable ties that are provided in the kit. See Figures 13c and 13d.

    • Note: Be sure to use cable ties at every bend.

    

34. Locate the trailer ABS supply connecting on the trailer light harness underneath the PDC box. See Figures 14a and 14b.

35. Connect the trailer ABS 1-way connector from the new harness to the trailer ABS supply 1-way connector from the trailer lights harness. See Figure 14c.

36. Re-install the cable ties that were previously removed under the PDC box when securing the new trailer ABS harness with the other harnesses. See Figure 14d.

    

37. Re-install (8) bolts and washers back onto the chassis PDC cover using a 7/16” socket wrench. See Figure 15.

38. Re-install (4) bolts and washers for the transmission grate using a 9/16” socket wrench. See Figure 16a.

39. Re-install (4) bolts, nuts, and (8) washers for the chassis PDC grate using a 9/16” socket wrench and 9/16” wrench to hold the nuts in place below the grate, see Figure 16b.

    

40. Re-connect the negative battery cable back onto the battery.

41. Remove “Lock Out, Tag Out” plaque.

42. Return vehicle to service.