TRAILER LIGHTS INOPERATIVE (12-VOLT TRAILER) (Cont)

TM 9-2320-285-24-1

2-20.

LIGHT SYSTEMS TROUBLESHOOTING (CONT)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. TRAILER LIGHTS INOPERATIVE (12-VOLT TRAILER) (Cont)

Step 2.

Check for continuity of light bulbs in inoperative circuits.

a. If trailer light bulb is defective, replace.

b. If trailer light bulb is not defective, go to step 3 below.

Step 3.

Check trailer lighting cable and 12V receptacle pins for open ground circuit (white electrical lead).

a. If components are damaged, repair or replace (para 2-31f or 2-30).

b. If components are not damaged, go to step 4 below.

Step 4.

Disconnect electrical leads for inoperative light circuit from 15 ampere circuit breaker (para 2-30).

Use an ohmmeter to check 15 ampere circuit breaker for continuity.

a. If ohmmeter indicates more than 1 ohm, replace circuit breaker (para 2-30).

b. If ohmmeter indicates less than 1 ohm, go to step 4 below.

Step 5.

Check if turn signal lights operate.

a. If turn signal lights do not operate, go to Malfunction 3, step 2.

b. If turn signal lights operate, go to step 5 below.

Step 6.

Disconnect electrical leads from trailer light switch and headlight switch (para 2-26a(4) and 2-

26a(7)).

Use an ohmmeter to check trailer light switch and headlight switch for continuity.

a. If a switch is defective, replace (para 2-26a(4) or 2-26a(7)).

b. If switches are not defective, go to step 6 below.

Step 7.

Use an ohmmeter to check wiring between switches and 15 ampere circuit breakers for open circuit.

Repair defective wiring by splicing a new length of the same size (gage) wire.

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