4-13. 24 VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
6. BLACKOUT TAILLIGHT(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)
24 vdc cable assembly connected to truck,
Locknut (Item 31, Appendix I)
Packing, Preformed (Item 59, Appendix I)
Parking brake applied, (TM 9-2320-364-10)
The following troubleshooting procedures cover the left blackout taillight, but they apply to both blackout taillights.
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.
Truck electrical system OK.
Does at least one blackout
All other trailer lights operate.
taillight operate when power
Taillights operate indicating
REASON FOR QUESTION
LED composite light ground
If no blackout taillights operate,
fault is in 24 vdc cable through
wire 1680C-19. If at least one
blackout taillight operates, fault
is in rear junction box through
Blackout taillight faulty.
Blackout taillight lamp faulty.
Wire 1680/24-27 faulty.
24 vdc cable faulty.
Connector MC15 faulty.
Front junction box faulty.
Wire 1680C-19 faulty.
Go to Step 6 of this
Rear junction box faulty.
If composite lights
are installed, go to
Step 2 of this Fault.
If LED composite
lights are insalled,
go to Step 5 of this