Table 1. Blackout Light Circuits Troubleshooting Procedures.

TM 9-2320-303-24-1

Table 1. Blackout Light Circuits Troubleshooting Procedures.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

One Or More Blackout (B/O) Marker Lights 1. Inspect light bulbs.

Not Operating.

2. Remove

lamp(s)

from

If continuity is indicated, go to

defective circuit(s). Check for

step 3. If no continuity is

continuity between socket and

indicated, replace lamp(s) (WP

ground.

0082 00).

3. Disconnect ground (B/O) If continuity is indicated, repair

marker light(s). Check for lead(s) 421A. If no continuity is

continuity between ground indicated, repair ground lead(s).

lead(s) and ground.

None Of The Blackout (B/O) Drive Lights 1. Inspect light bulbs.

Operate.

2. Disconnect B/O drive lights If +24 VDC is present, go to step

relay from connector. Check 3. If no voltage is present, repair

for +24 VDC at connector 30. lead 421V.

3. Check for +24

VDC

at If +24 VDC is present, go to step

connector 85.

4. If no voltage is present, repair

lead 420D.

4. Check for continuity between If continuity is indicated, go to

connector 86 and ground.

step 5. If no continuity is

indicated, repair ground lead.

5. Install jumper wires between

If +24 VDC is present, repair lead

connector 30 and stoplights

421P or lead 421K. If no voltage

relay, connector 85 and

is present, replace B/O drive lights

stoplights relay, and connector

relay (WP 0072 00).

86 and stoplights relay. Check

for +24 VDC at stoplights relay

contact 87.

One Or More Blackout (B/O) Drive Lights 1. Inspect light bulb(s).

Not Operating.

2. Remove lamp from defective If continuity is indicated, go to

circuit. Check for continuity step 3. If no continuity is

between socket and ground.

indicated, replace lamp (WP 0082

00).

3. Disconnect ground (B/O) drive If continuity is indicated, repair

lights. Check for continuity lead 421P. If no continuity is

between ground lead(s) and indicated, repair ground lead(s).

ground.

4. Check for +24 VDC at If +24 VDC is present,

connector 421K at trailer troubleshoot trailer circuit(s). If

receptacle(s).

no voltage is present, repair

lead(s) 421K.

0010 00-16