TM-9-2320-283-20-1

TRUCK TRACTOR, LINE HAUL, 50,000 GVWR, 6X4, M915A1

TECHNICAL MANUAL; ORGANIZATIONAL MAINTENANCE PART 1 OF 3

DECEMBER 1983

TM-9-2320-283-20-1 - Page 111 of 926

TM 9-2320-283-20-1

PRINCIPLES OF OPERATION.

1-23.

CAB HEATING AND VENTILATING SYSTEM (Continued)

DEFROSTER HOSE.

Supplies heat for defrosting front windshield.

DRIVER HEAT HOSE.

Supplies heat to driver’s side of cab compartment.

RECIRCULATION CONTROL LEVER.

Actuates shutter inside heater.

Connected by cable to recirculation vent control

knob.

FRESH VENT CONTROL LEVER.

Actuates shutters at fresh air vent.

Connected by cable to fresh vent control knob.

AIR DIFFUSER.

Contains baffles that direct flow of air to heater or cab compartment.

HEATER CORE.

Circulates hot water through tubing and transfers heat to air coming from air diffuser.

HEATER FAN MOTOR.

Drives two fans for distributing heat and air.

Actuated by fan switch.

AIR DEFLECTOR(S).

Supply heat to lower area of cab compartment.

PASSENGER HEAT CONTROL LEVER.

Actuates flap at heat vent for passenger.

Connected by cable to passenger pull knob.

DRIVER HEAT CONTROL LEVER.

Actuates flap at heat vent for driver.

Connected by cable to driver pull knob.

CONTROL VALVE.

Controls heater temperature by regulating flow of hot water to heater core.

Cable from heater knob in

cab opens valve as knob is pulled.

Valve is spring loaded to close as knob is pushed in.

Some water passes through this valve even when it is fully closed.

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