4-14. 12-VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
5. STOPLIGHT(S) DO 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)
Locknut (Item 31, Appendix I)
12 vdc cable assembly connected to
Packing, Preformed (Item 59, Appendix I)
truck, (TM 9-2320-364-10)
Parking brake applied, (TM 9-2320-364-10)
The following troubleshooting procedures cover the left stoplight, but they apply to both stoplights.
All electrical wires and components listed in this troubleshooting procedure are illustrated and located in FO-1.
Trailer may be equipped with composite lights or LED composite lights.
If LED composite light is installed, go to Step 4.1 of this Fault.
Truck electrical system OK.
on Page 4-167
All other lights on trailer
REASON FOR QUESTION
Is continuity measured across
If light lamp filament is faulty,
lamp will not operate.
Stoplight lamp faulty.
Composite light faulty.
12 vdc cable faulty.
Connector MC16 faulty.
Front junction box faulty.
Wire 1003-17 faulty.
Rear junction box faulty.
Wire 1003/22-30 faulty.
lamp (Para 4-29).
Verify repair, go to
Step 10 of this Fault.