4-14. 12-VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).
19. ALL MARKER LIGHTS 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)
Wheels chocked, (TM 9-2320-364-10)
Parking brake applied, (TM 9-2320-364-10)
12 vdc cable assembly connected to truck,
All electrical wires and components listed in this troubleshooting procedure are illustrated and located in FO-1.1.
Truck electrical system OK.
All other trailer lights operate.
REASON FOR QUESTION
If voltage is not present between
Are 10 to 14 vdc measured
terminals B and A on 12 vdc cable
12 vdc cable faulty.
between terminals B and A
assembly, rear side marker light
Wire 1012-2 faulty.
on trailer end of 12 vdc
and rear marker lights will not
Diode assembly faulty.
Wire 1012B faulty.
Repair (Para 4-31) or
replace (Para 2-9) 12
vdc cable. Verify
repair, go to Step 3 of