4-14. 12-VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
1. FRONT SIDE MARKER LIGHT DOES NOT OPERATE.
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)
12 vdc cable assembly connected to
truck, (Para 2-9)
The following troubleshooting procedures cover the left front side marker light, but they apply to both front side marker
All electrical wires and components listed in this troubleshooting procedure are illustrated and located in FO-1.
Truck electrical system OK.
on Page 4-123
All other trailer lights operate.
REASON FOR QUESTION
Is continuity measured across
If lamp filament is faulty, light
will not operate.
front side marker light lamp?
Light lamp faulty.
Marker light faulty.
Wire 1012-24 faulty.
Wire 1435-23 faulty.
Replace light lamp
Verify repair, go to
Step 7 of this Fault.