4-13. 24 VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
17. BLACKOUT TAILLIGHT(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 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-1.1.
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
(wire 1435) OK.
Fault is in 24 vdc cable through
wire 1680C. If at least one
blackout taillight operates, fault
is in rear junction box through
LED composite light.
Wire 1680C/24 faulty.
Wire 1680C faulty.
LED composite light faulty.
Go to Step 3 of this