BLACKOUT TAILLIGHT(S) DO NOT OPERATE (S/N YB6122 075 AND UP).

TM 9-2330-385-14

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

17. BLACKOUT TAILLIGHT(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

Equipment Condition

Multimeter (Item 28, Appendix J)

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

Personnel Required

24 vdc cable assembly connected to truck,

Two

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

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

NOTE

The following troubleshooting procedures cover the left blackout taillight, but they apply to both blackout taillights.

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

START

KNOWN INFO

TEST OPTIONS

Truck electrical system OK.

Visual inspection.

Does at least one blackout

All other trailer lights operate.

taillight operate when power

Taillights operate indicating

REASON FOR QUESTION

is applied?

LED composite light ground

(wire 1435) OK.

Fault is in 24 vdc cable through

wire 1680C. If at least one

POSSIBLE PROBLEMS

blackout taillight operates, fault

is in rear junction box through

LED composite light.

Wire 1680C/24 faulty.

Wire 1680C faulty.

LED composite light faulty.

Go to Step 3 of this

Fault.

YES

4-118.40