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The MIL7 exam has 50 questions and runs 1 hours.
These 10 free MIL7 questions are organized by exam domain, so you can see how each part of the ASE Military Tactical Wheeled Vehicle Certification - MIL7 Heating, Ventilation & Air Conditioning (HVAC) blueprint is tested. Reveal the answer and explanation under each question.
An operator reports a rapid rattle inside the cab. At a fixed engine speed, each change in blower speed immediately changes the rattle's frequency. Engaging and disengaging the compressor has no effect on the noise. Where should the inspection begin?
Correct answer: B - The blower wheel, housing, and motor mounts.
Two technicians check the same A/C system on successive shifts. The first records a 9°C vent temperature at 28°C ambient, with recirculation selected and the engine at 1,500 rpm. The second records 17°C at 40°C ambient, with fresh air selected and the engine idling. No service has occurred between checks. Before treating the warmer reading as evidence of a fault, the second technician should:
Correct answer: A - Repeat the prescribed test, using the current ambient-temperature performance limits.
A tactical truck cools adequately while moving but poorly when stationary. With engine speed held at 1,500 rpm, the high-side pressure is 310 psig and the center-vent temperature is 19°C. Directing a shop fan through the condenser lowers these readings to 225 psig and 8°C without changing engine speed. Refrigerant identity and charge mass have been verified. Which condition best explains the improvement?
Correct answer: C - Inadequate airflow across the condenser.
Although the vehicle label specifies R-134a, two correctly performed refrigerant-identifier tests confirm a mixture of refrigerants. The shop's recovery/recycling machine is approved only for uncontaminated R-134a. Which recovery arrangement is appropriate before opening the system?
Correct answer: A - Equipment rated for the mixture and a separate, labeled recovery cylinder.
An R-134a system has stabilized at 70°F with the engine off. Both service gauges read 71 psig, matching the pressure-temperature chart at that temperature. Technician A says these readings confirm that the system contains its specified refrigerant charge. Technician B says compressor pumping performance cannot be determined from these readings. Who is correct?
Correct answer: B - Technician B only.
A compressor and receiver-drier are being replaced in a clean, unflushed A/C system. The drier's oil allowance has already been added. The dry-system oil capacity is 240 mL; the new compressor contains 180 mL, the old compressor drains 70 mL, and recovery separates another 10 mL that has not been replaced. The manufacturer calls for matching the old compressor's drained oil quantity, with recovery losses replenished separately. Which remaining adjustment preserves the oil balance?
Correct answer: C - Remove 110 mL from the replacement; add 10 mL for the recovery loss.
During a cold-weather road test, engine coolant temperature remains near 58°C and cab heat is weak. An independent temperature check confirms the reading. The installed thermostat is rated to begin opening at 82°C, yet a flow check shows substantial coolant circulation through the radiator at 50°C. Fan operation is normal. Which fault accounts for both the warm-up pattern and the poor heater output?
Correct answer: D - A thermostat that is stuck partly open.
A greasy film repeatedly forms on the inside of the windshield when the heater is used. Defroster airflow is strong, but a sweet odor enters the cab and the cold coolant level has been falling without an external leak being found. Which area should be checked for leakage?
Correct answer: D - The heater core and its coolant connections.
Three voltage readings are taken while a 24-volt blower runs slowly on HIGH: 25.2 V across the batteries, 24.9 V from the motor's positive terminal to battery negative, and 4.5 V from the motor's negative terminal to battery negative. The circuit uses a direct ground return, not electronic ground-side speed control. What voltage is actually across the motor, and which circuit should be repaired first?
Correct answer: A - 20.4 V; the motor's ground-return circuit.
The electric condenser fan remains stopped during an output-command test. Its relay clicks, and voltage across the relay coil is 24.8 V. With the fan connected, the relay's load-input terminal measures 24.8 V to battery negative, but its load-output terminal measures 0.2 V. The fan runs normally when a fused test supply feeds the output wire. The failure is in the:
Correct answer: C - Relay's high-current contacts.
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