4-14. 12-VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
14. 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)
12 vdc cable assembly connected to
truck, (Para 2-9)
Parking brake applied, (TM 9-2320-364-10)
Wheels chocked, (TM 9-2320-364-10)
The following troubleshooting procedures cover the left taillight, but they apply to both 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 taillight
operate when power is
REASON FOR QUESTION
If no taillights operate when pow-
er is applied, fault is in the 12
Wire 1435 faulty.
vdc cable assembly through rear
Wire 1008B/21 faulty.
junction box assembly. If at
12 vdc cable assembly faulty.
least one taillight operates, fault
Wire 1008B faulty.
is between rear junction box and
Wire 1008-1 faulty.
LED composite light.
Diode assembly faulty.
LED composite light faulty.
Go to Step 4 of this