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 168 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-10.

TROUBLESHOOTING SYMPTOM INDEX.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

COOLING SYSTEM

16 NO CAB HEAT.

Step 1

Check heater and heater air hoses for leaks or blockage.

a

Adjust cables, if necessary (para 3-301).

b

Replace heater air hoses (para 3-296).

c

Replace or repair heater (para 3-298).

Step 2

Check for closed water control valve.

a

Open valve.

b

Bleed heater (para 3-52).

Step 3

With engine running and radiator cap removed, check for proper coolant flow and level.

a

Replace thermostat (para 3-59).

b

Replace water pump (para 3-64).

c

Replace radiator (para 3-53).

Step 4

Check fan clutch operation.

a

Check fan clutch air valve tubes for cracks.

Replace, if necessary (para 3-163).

b

Replace fan clutch air valve (para 3-66).

c

Replace fan clutch (para 3-65).

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