4-14. 12-VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
18. REAR SIDE MARKER LIGHTS AND REAR MARKER LIGHTS 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)
Wheels chocked, (TM 9-2320-364-10)
Parking brake applied, (TM 9-2320-364-10)
12 vdc cable assembly connected to truck,
All electrical wires and components listed in this troubleshooting procedure are illustrated and located in FO-1.1.
Truck electrical system OK.
All other trailer lights operate.
REASON FOR QUESTION
Are 10 to 14 vdc measured on
If voltage is not supplied to rear
wire 1012B at rear junction
Wire 1012B faulty.
junction box on wire 1012B,
lights will not operate.
Repair Wire 1012B
(see schematic, Fig
FO-1.1) or replace
trailer main wire
harness (Para 4-30.1).
Verify repair, go to
Step 2 of this Fault.