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 953 of 1313
ONE OR MORE TRAILER LIGHTS INOPERATIVE - Continued
STEP
5.
IS TRAILER LIGHTING SYSTEM CABLE IN GOOD CONDITION?
a.
Check trailer lighting system cable for continuity and for broken or frayed condition.
b.
Disconnect both ends of the trailer lighting system cable.
T0123DAA
Figure 5.
Trailer Lighting System Cable.
c.
Open and lock hinged covers on trailer lighting system cable.
d.
Set up multimeter to measure resistance.
e.
Connect multimeter red lead to socket on one end of the cable.
f.
Connect multimeter red lead to corresponding socket on other end of the cable.
g.
Meter reading should be less than 200 ohms for each measurements.
CONDITION/INDICATION
IS TRAILER LIGHTING SYSTEM CABLE IN GOOD CONDITION?
DECISION
NO - Replace defective trailer connecting cable. Go to Step (7) to verify problem is solved.
YES - Go to Step (6).
STEP
6.
IS WIRING FROM MAIN SWITCH TO LAMP IN GOOD CONDITION?
NOTE
Perform these steps if faulty trailer is available.
a.
Check for battery voltage at non-operating lamp holder.
b.
Connect trailer lighting system cable to vehicle trailer receptacle and trailer.
c.
Remove faulty circuit lamp.
d.
Place battery switch to ON position.
TM 9-2320-272-23-1
0113
0113-6
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