4-13. 24 VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
14. REAR MARKER LIGHT(S) DO NOT OPERATE (S/N YB6122 075 AND UP).
Tools and Special Tools
Tool Kit, General Mechanic's: Automotive
(Item 50, Appendix J)
Multimeter (Item 28, Appendix J)
Engine OFF, (TM 9-2320-364-10)
24 vdc cable assembly connected to truck,
Parking brake applied, (TM 9-2320-364-10)
Wheels chocked, (TM 9-2320-364-10)
The following troubleshooting procedures cover one rear marker light, but they apply to all rear marker lights.
All electrical wires and components listed in this troubleshooting procedure are illustrated and located in FO-1.1.
Truck electrical system OK.
Does at least one rear or rear
All other lights on trailer
side marker light operate?
REASON FOR QUESTION
If no rear or rear side marker
lights operate, fault is in trailer
Wire 1012B faulty.
main wire harness wire 1012B.
Wire 1435 faulty.
If at least one rear or rear side
Rear marker light faulty.
marker light operates, fault is in
rear junction box through rear
Repair wire 1012B
(see schematic, Fig
FO-1.1) or replace
trailer main wire
4-30.1). Verify repair,
go to Step 4 of this