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 907 of 1313
FUEL GAUGE INOPERATIVE - Continued
STEP
2.
ARE CIRCUIT WIRES 28 OR 29 FROM FUEL LEVEL SENDING UNIT TO FUEL SELECTOR SWITCH IN
GOOD CONDITION?
a.
Check for 5 to 8 VDC at fuel selector switch terminal.
b.
Refer to point to point schematics.
T0090DAA
28
28
29
Figure 2.
Fuel Level Gauge Test.
c.
Place battery switch to the OFF position.
NOTE
Make sure fuel selector switch is set to side being tested.
d.
Disconnect circuit 28 or 29 wire from fuel selector switch (wire 28 for left hand tank, wire 29 for right hand
tank).
e.
Place battery switch to ON position.
f.
Set multimeter to measure VDC.
g.
Connect multimeter red lead to open circuit 28 (pin B) or 29 (pin D) terminal at fuel selector switch.
h.
Connect multimeter black lead to vehicle chassis ground.
NOTE
If 5 to 8 VDC is present, circuit 28 or 29 wire is faulty.
i.
Meter reading should be between 5 and 8 VDC.
CONDITION/INDICATION
ARE CIRCUIT WIRES 28 OR 29 FROM FUEL LEVEL SENDING UNIT TO FUEL SELECTOR SWITCH IN
GOOD CONDITION?
DECISION
YES - Go to Step (3).
NO - Repair or replace circuit 28 or 29 wire (Volume 3, WP
0352). Go to Step (6) to verify problem is solved.
TM 9-2320-272-23-1
0107
0107-4
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