TM 55-1930-203-10
2-17. Cab Heater
The LARC cab is equipped with a hot water heater (27, sheet 3, fig. 2-1) for windshield defrosting and for heating the cab. The heater
has two hoses connecting the heater and defrosting units together. Hot water that circulates through the heater flows from the aft
port engine cooling system. A toggle switch located on the circuit breaker panel (25) turns the heater fan on and off. The defroster
control (26) is used to vary the amount of air flow to the windshield.
2-18. Foot Throttle
All engines may be operated simultaneously by the foot throttle (28, sheet 3, fig. 2-1) located at the right side of the steering column.
Acceleration from idle to any desired governed speed is obtained by depressing the pedal. When the pedal is completely released,
engines will operate at idling speed.
2-19. Brake Pedal
CAUTION
Whenever the LARC is left on a grade or in one place for any length of time, dig the wheels in to
prevent the LARC from moving. If situated on hard ground, park crossways to the grade.
The brake pedal (29, sheet 3, fig. 2-1), located to the left of the foot throttle, controls braking action of the four wheels. When the
brake pedal is pressed, air activates valves which allow air from the supply tanks to flow to the brakes. Two airbrakes are attached to
each of the four miter boxes which restrain the horizontal miter box shafts to accomplish braking action. When the brake pedal is
released, all air is vented to the atmosphere from air lines and air brakes. The brake pedal may also be used as a parking brake for
short periods of time by placing the dog of the brake pedal locking devices (15, sheet 1) over the toe end of the brake pedal when it is
fully applied. When the LARC is to be parked for any length of time, airbrake shutoff valves (1, fig. 2-2) that isolate air in the aft
airbrakes must be closed.
2-20. Airbrake Shutoff Valves
CAUTION
Whenever the LARC is left on a grade, or in one place for any length of time, dig the wheels in to
keep the LARC from moving. If situated on hard ground, park crossways to the grade. Apply the
parking brakes after the LARC has stopped. Be sure to open the shutoff valves before attempting to
move the LARC. Failure to do so will damage the brakes (3, fig. 2-2).
Each air supply line leading to the aft airbrakes is provided with a shutoff valve (1, fig. 2-2). These shutoff valves are used to isolate
air in the aft brakes for parking. Both valves must be closed when the LARC is parked for an extended period of time. To close the
valves, handles are turned clockwise.
2-21. Machinery Light Switches
Two switches (fig. 2-4) control the lights that illuminate the machinery area. These switches are located near the access ladder and
center hatch, port and starboard. The forward switch controls the upper machinery compartment lights. The aft switch controls two
lights under the cargo deck in the marine gear compartment. Switches at the fixtures control the wing compartment lights.
2-13
