TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 949 of 1313
ONE OR MORE TRAILER LIGHTS INOPERATIVE - Continued
STEP
1.
DOES CORRESPONDING LIGHTING SYSTEM ON TRUCK FUNCTION?
a.
Place battery switch to ON position.
T0120DAA
Figure 1.
Lighting System.
b.
Place truck main light switch in position corresponding to inoperative system on trailer.
NOTE
For stoplight circuit test, air pressure must be maintained at operating pressure and brake
pedal must be depressed.
c.
Check if corresponding lighting system on truck operates.
CONDITION/INDICATION
DOES CORRESPONDING LIGHTING SYSTEM ON TRUCK FUNCTION?
DECISION
NO - Blackout marker lights do not operate. Perform Blackout Drive Or Marker Light Inoperative
troubleshooting (WP
0094).
NO - Service or blackout stoplights do not operate. Perform Stoplights Inoperative (Service or Blackout)
troubleshooting (WP
0095).
NO - Tail and marker lights do not operate. Perform Tail and Marker Lights Inoperative troubleshooting
(WP
0096).
YES - Go to Step (2).
TM 9-2320-272-23-1
0113
0113-2
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