4-13. 24 VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
18. BLACKOUT STOPLIGHT(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)
Truck air pressure charged, (TM 9-2320-364-10)
Wheels chocked, (TM 9-2320-364-10)
The following troubleshooting procedures cover the left blackout stoplight, but they apply to both blackout stoplights.
All electrical wires and components listed in this troubleshooting procedure are illustrated and located in Figure FO-1.1.
Truck electrical system OK.
Does at least one blackout
All other trailer lights operate.
stoplight operate when
Taillights operate indicating
REASON FOR QUESTION
brakes are applied?
LED composite light ground
If no blackout stoplights operate,
(wire 1435) OK.
fault is 24 vdc cable assembly
through wire 1678C. If at least
one stoplight operates, fault is
rear junction box through LED
Wire 1678C/23 faulty.
Wire 1678C faulty.
LED composite light faulty.
Go to Step 3 of this