TM 9-2320-279-10-1
Change 8
2-11
Controls and Indicators (Cont)
Legend for Figure 2-6. Heater Compartment Controls and Indicators.
Key
Control or Indicator
Function
1
Trailer Handbrake Control
Operates trailer brakes and is used only to
TEST the trailer brakes.
2
JACOBSR ENGINE BRAKE
ON-OFF Switch
Supplies or shuts off electrical power to
JACOBSR ENGINE BRAKE.
3
JACOBSR ENGINE BRAKE
Indicator
Lights (green) when JACOBSR ENGINE
BRAKE ON-OFF switch is in ON position.
4
JACOBSR ENGINE BRAKE
HIGH-LOW Switch
Selects number of engine cylinders used for
engine braking action. HIGH position provides
maximum braking. LOW position provides less
engine braking.
5
AIR Control
Controls amount of outside air entering cab
through fresh air vent.
6
FAN Control
Controls speed of heater fan.
7
HEAT Control
Controls amount of hot air entering cab.
8
DEFROST Control
Controls amount of hot air blown on windshield.
9
PTO ENGAGE Indicator
Lights (red) when PTO ENGAGE control is in
ON position.
10
CRANE OUTRIGGER
EXTENDED Indicator
Lights (red) when outriggers are extended
(M977 and M985 only).
11
PTO ENGAGE Control
Supplies or shuts off electrical power to power
takeoff (PTO).
12
Utility Outlet
Supplies electrical power to operate beacon light
and work lamp.
13
Light Control
Controls all electrical power to all parts of
lighting system.
14
WASHER Control (Non--FHTV)
Controls spray of cleaning fluid on
windshield.
15
WIPER Control
(Right)(Non-FHTV)
Controls operation of right windshield wiper.
16
WIPER Control (Left)
(Non-FHTV)
Controls operation of left windshield wiper.
17
WIPER/ WASHER Switch
(FHTV only)
Controls both wipers and washer. Turn
clockwise to start wipers. Turn fully clockwise
for high speed. Press to start washer.
18
WORK LIGHT Switch
(M1977-CBT, M983 and
M984A1 only)
Up position (on) turns on work lights. Down
position (off) turns work lights off.
19
DOME Light Switch
Up position (on) turns cab dome light on. Down
position (off) turns cab dome light off.
20
CL LPS Switch
Up position (on) turns clearance lamps on.
Down position (off) turns clearance lamps off.
