FRONT MARKER LIGHT(S) DO NOT OPERATE (S/N YB6122 075 AND UP).

TM 9-2330-385-14

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

12. FRONT MARKER LIGHT(S) 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)

Multimeter (Item 28, Appendix J)

Equipment Condition

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

Personnel Required

24 vdc cable assembly connected to truck,

Two

(Para 2-9)

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

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

NOTE

The following troubleshooting procedures cover the left front side marker light, but they apply to all front

marker lights.

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

Truck electrical system OK.

Voltage test.

on Page 118.3

All other trailer lights operate.

REASON FOR QUESTION

POSSIBLE PROBLEMS

If voltage is not supplied to

Are 22 to 28 vdc measured on

front marker light, marker light

Wire 1012B faulty.

wire 1012B at front marker

will not operate.

light?

Wire 1435 faulty.

Front marker light faulty.

Repair wire 1012B (see

schematic Fig FO-1.1) or

replace trailer main wire

harness (Para 4-30.1).

Verify repair, go to Step 3

of this Fault.

YES

4-118.2