ALL TRAILER LIGHTS DO NOT OPERATE (S/N YB6122 075 AND UP). -725550332

TM 9-2330-385-14

4-13. 24-VOLT ELECTRICAL SYSTEM TROUBLESHOOTING PROCEDURES (CONT).

23. ALL TRAILER LIGHTS DO NOT OPERATE (S/N YB6122 075 AND UP).

INITIAL SETUP

Tools and Special Tools

References

Tool Kit, General Mechanic's: Automotive

TM 9-2320-364-10

(Item 50, Appendix J)

Equipment Condition

Multimeter (Item 28, Appendix J)

Engine OFF, (TM 9-2320-364-10)

24 vdc cable assembly connected to truck,

(Para 2-9)

Personnel Required

Two

Parking brake applied, (TM 9-2320-364-10)

Wheels chocked, (TM 9-2320-364-10)

NOTE

All electrical wires and components listed in this troubleshooting procedure are illustrated and located in FO-1.1.

START

KNOWN INFO

TEST OPTIONS

WARNING

Read WARNING

Continuity test.

Truck electrical system OK.

on Page 4-118.73

REASON FOR QUESTION

POSSIBLE PROBLEMS

Is continuity measured

If continuity is not measured

24 vdc cable faulty.

between 24 vdc cable,

between 24 vdc cable

Wire 1435 faulty.

terminal pin D and L, and a

connector, terminal pin D and

known good ground, 24 vdc

pin L, and a known good

cable is faulty.

ground?

Repair 24 vdc cable

(Para 4-31) or replace

24 vdc cable

(Para 2-9).

Verify repair, go to

Step 2 of this Fault.

YES

Repair wire 1435 (see

schematic, Fig FO-3)

or replace trailer main

wire harness (Para

4-30.1. Verify repair,

go to Step 2 of this

Fault.

4-72

-118.72