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 954 of 1313
ONE OR MORE TRAILER LIGHTS INOPERATIVE - Continued
e.
Place truck main light switch in position corresponding to inoperative system on trailer.
f.
Set up multimeter to measure VDC.
T0119DAA
Figure 6.
Trailer.
g.
Connect multimeter red lead to to center contact inside lamp holder or wire connector.
h.
Connect multimeter black lead to to good ground.
NOTE
•
For stoplight circuit test, air pressure must be maintained at operating pressure and
brake pedal must be depressed.
•
If voltage is present, wiring to the lamp is in good condition.
i.
Meter reading should be greater than 18 VDC.
CONDITION/INDICATION
IS WIRING FROM MAIN SWITCH TO LAMP IN GOOD CONDITION?
DECISION
NO - Notify supervisor. Perform trailer lighting troubleshooting.
YES - Replace faulty lamp.
TM 9-2320-272-23-1
0113
0113-7
Back to Top
