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 853 of 1313
SYSTEM OPERATES INCORRECTLY IN ONE OR MORE POSITIONS OF DIRECTIONAL SIGNAL CONTROL
LEVER - Continued
STEP
1.
DO THE ELECTRICAL CONTACTS INSIDE THE DIRECTIONAL SIGNAL CONTROL UNIT WORK
PROPERLY WHEN IN "NEUTRAL" POSITION?
a.
Set up multimeter to measure resistance.
b.
Disconnect control unit harness connector from directional signal control unit.
c.
Remove indicator lamp from directional signal control.
d.
Set control lever to "Neutral" position.
T0782DAA
DIRECTIONAL SIGNAL CONTROL
LEVER IN “NEUTRAL” POSITION
TEST PROBE LEADS
BLACK (-)
H
H
H
H
D
D
F
A
B
C
E
C
E
G
OPEN
OPEN
OPEN
OPEN
OPEN
SHORTED
SHORTED
RED (+)
CONTINUITY
INDICATION
Figure 1.
Directional Signal Control Neutral Position.
e.
Connect multimeter black lead to first location listed in graphic. Refer to point to point schematics.
f.
Connect multimeter red lead to first location listed in graphic.
g.
Note reading and compare to the first location listed under "Continuity Indication". Meter reading should
be greater than 10,000 ohms for open indication.
h.
Move black and red multimeter leads to each location listed in the graphic and compare the readings to
those listed under "Continuity Indication".
CONDITION/INDICATION
DO THE ELECTRICAL CONTACTS INSIDE THE DIRECTIONAL SIGNAL CONTROL UNIT WORK PROPERLY
WHEN IN "NEUTRAL" POSITION?
DECISION
NO - Replace directional signal control unit (Volume 2, WP
0317). Go to Step (5) to verify problem is solved.
YES - Go to Step (2).
TM 9-2320-272-23-1
0099
0099-2
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