TM-9-2320-279-20-1
M977 SERIES, 8x8 HEAVY EXPANDED MOBILITY TACTICAL TRUCKS (HEMTT)
TECHNICAL MANUAL; MAINTENANCE INSTRUCTIONS; ORGANIZATIONAL MAINTENANCE, VOLUME 1 OF 3
TM-9-2320-279-20-1 - Page 136 of 985
TM 9-2320-279-20-1
Troubleshooting Index (Cont)
2-15. TROUBLESHOOTING INSTRUCTIONS (CONT).
Table 2-7. System Symptom Index
(Cont)
Troubleshooting
Procedure
Page
DUAL AIR BRAKE SYSTEM (CONT)
8.
Brakesoverhea
t ..................................................................
2-172
9.
Front axle parking brakes will not apply (M984El)
.................................
.
2-173
10.
Front axle parking brakes will not release (M984El)
.................................
2-174
ELECTRICAL SYSTEM
1.
Battery weak or fails to maintain charge
..........................................
.
2-114
2.
Engine brake will not operate
.....................................................
2-114.1
3.
Heater fan motor will not operate
...................................................
2-115
4.
Power take off (PTO) switch will not engage
.........................................
. 2-118
5.
Light not workin
g ................................................................
2-120
6.
Dimmer switch fails to operate
....................................................
. 2-121
7.
Stoplights do not work
............................................................
. 2-122
8.
Air pressure warning light and buzzer do not work when air pressure drops below
approximately 65 psi (448 kPa)
....................................................
. 2-123
9.
Domelight does not work
..........................................................
. 2-125
10.
ENGINE STOP switch does not activate fuel shutdown solenoid
......................
.
2-126
11.
Work light does not work.
...............................................
2-126
11.1
Work lights fail to work (M984E1) .
......................................
2-127
12.
Air dryer constantly exhausts air
...................................................
2-128
13.
Marker and clearance lights do not work
............................................
2-129
14.
Ether starting aid does not work
...................................................
. 2-130
15.
Electric gages do not work
.....................................................
2-131
16.
Switches do not work
..........................................................
2-131
17.
Trailer electrical system does not work
.............................................
. 2-132
18.
Turn signals do not operate
.........................................................
2-132
19.
Oil-water indicator and buzzer do not work when oil pressure drops below
8psi(55kPa)
...................................................................
2-13 4
20.
Oil-water indicator and buzzer do not work when coolant temperature rises
above 230°F(110° C
) ......................................................................
2-134 .2
ENGINE
1.
Fails to cran
k ....................................................................
2-59
2.
Fails to develop full power/does not run smoothly
3.
Oil pressure low .
.....
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
. . . . . . .
...........
.............................
2-63
............
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
4.
Overheats
2-63
2-64
5.
High oil consumptio
n .............................................................
2-66
. . . . . . . . . . . . . . . . . . . . . . . . .
5.1
High crankcase pressure . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . .
..
6.
ENGINE HIGH IDLE does not operate (M977, M985)
7.
ENGINE HIGH IDLE does not operate (M983) . . . . .
8.
Engine speed control does not operate (M978) . . . . . .
9.
ENGINE HIGH IDLE does not operate when craning
9.1
ENGINE HIGH IDLE does not operate (M984El) . . .
9.2 ENGINE HIGH IDLE does not operate when craning
. . . . . . . . . . . . . . . . . . . . . . . . .
....
..
. . . . . . . . . . . . . . . .
. .
......
M984, M985El)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..
..
. . . . . .
M984El) .
. . . .
2-66
2-66
2-70
2-74
2-78
2-82
. . . . . . . . . .
.. 2-89
10.
ENGINE HIGH IDLE does not operate when using heavy-duty winch (M984) . . . .
. . . .
10.1
ENGINE HIGH IDLE does not operate when using heavy-duty winch in
remote control (M984El) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.2
ENGINE HIGH IDLE does not operate when using heavy-duty winch in
manual control (M984El
)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.3
ENGINE HIGH IDLE does not operate when using retriever system (M984El) . . . . . . .
2-99
2-103
2-106
2-110
2-52
Change 3
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