Mar 28, 2024  
2021-2022 Course Catalog 
    
2021-2022 Course Catalog [ARCHIVED CATALOG]

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ATG 326 - GM Auto AC Systems

Credits: 3
Lecture Hours: 2
Lab Hours: 2
Practicum Hours: 0
Work Experience: 0
Course Type: Voc/Tech
Theory of operation of General Motors air conditioning systems leading to the diagnosis, service and repair of current models of GM vehicles.
Prerequisite: Admission to Automotive Service Educational Program (ASEP), ATG 312  and AUT 114  
Competencies
  1. Demonstrate safe work habits.
    1. Use proper eye protection.
    2. Select proper tools to work in a safe manner.
    3. Demonstrate a concern for the safety of fellow workers.
  2. Demonstrate knowledge of refrigeration principles.
    1. Explain laws governing heat and temperature.
    2. Discuss the history of air conditioning.
    3. Identify the refrigeration circuit.
  3. Demonstrate an understanding of laws concerning CFCs and HFCs.
    1. Describe the effects of the Montral Protocol.
    2. Explain the Federal Clean Air Act.
    3. Compare various refrigerants used by automotive manufacturers.
    4. Complete a test for CFC recovery.
    5. Understand the SAE standards that apply to air conditioning.
    6. Operate refrigerant recovery and recycling equipment according to Federal laws.
  4. Air Conditioning System Diagnosis and Repair.
    1. Identify and interpret heating and air conditioning problems; determine necessary action.
    2. Research applicable vehicle and service information, vehicle service history, service precautions, and technical service bulletins.
    3. Performance test A/C system; determine necessary action.
    4. Identify abnormal operating noises in the A/C system; determine necessary action.
    5. Identify refrigerant type; select and connect proper gauge set; record temperature and pressure readings.
    6. Leak test A/C system; determine necessary action.
    7. Inspect condition of refrigerant oil removed from A/C system; determine necessary action.
    8. Determine recommended oil and oil capacity for system application.
    9. Using a scan tool, observe and record related HVAC data and trouble codes.
  5. Refrigerant System Component Diagnosis and Repair.
    1. Inspect and replace A/C compressor drive belts, pulleys, and tensioners; determine necessary action.
    2. Inspect, test, service or replace A/C compressor clutch components and/or assembly; check compressor clutch air gap; adjust as needed.
    3. Remove, inspect, and reinstall A/C compressor and mountings; determine recommended oil quantity.
    4. Identify hybrid vehicle A/C system electrical circuits and service/safety precautions.
    5. Determine need for an additional A/C system filter; perform necessary action.
    6. Remove and inspect A/C system mufflers, hoses, lines, fittings, O-rings, seals, and service valves; perform necessary action.
    7. Inspect A/C condenser for airflow restrictions; perform necessary action.
    8. Remove, inspect, and reinstall receiver/drier or accumulator/drier; determine recommended oil quantity.
    9. Remove, inspect, and install expansion valve or orifice (expansion) tube.
    10. Inspect evaporator housing water drain; perform necessary action.
    11. Diagnose A/C system conditions that cause the protection devices (pressure, thermal, and PCM) to interrupt system operation; determine necessary action.
    12. Determine procedure to Remove and reinstall evaporator; determine required oil quantity.
    13. Remove, inspect, and reinstall condenser; determine required oil quantity.
  6. Heating, Ventilation, and Engine Cooling Systems Diagnosis and Repair.
    1. Inspect engine cooling and heater systems hoses; perform necessary action.
    2. Inspect and test heater control valve(s); perform necessary action.
    3. Diagnose temperature control problems in the heater/ventilation system; determine PCM) to interrupt system operation; determine necessary action.
    4. Determine procedure to remove, inspect, and reinstall heater core.
    5. Check operation of electrical and mechanical cooling fans.
  7. Operating Systems and Related Controls Diagnosis and Repair.
    1. Inspect and test A/C-heater blower motors, resistors, switches, relays, wiring, and protection devices; perform necessary action
    2. Diagnose A/C compressor clutch control systems; determine necessary action.
    3. Diagnose malfunctions in the vacuum, mechanical, and electrical components and controls of the heating, ventilation, and A/C (HVAC) system; determine necessary action.
    4. Inspect and test A/C-heater control panel assembly; determine necessary action.
    5. Inspect and test A/C-heater control cables, motors, and linkages; perform necessary action.
    6. Inspect A/C-heater ducts, doors, hoses, cabin filters, and outlets; perform necessary action.
    7. Identify the source of A/C system odors.
    8. Check operation of automatic or semi-automatic heating, ventilation, and air-conditioning (HVAC) control systems; determine necessary action.
  8. Refrigerant Recovery, Recycling, and Handling.
    1. Perform correct use and maintenance of refrigerant handling equipment according to equipment manufacturer’s standards
    2. Identify and recover A/C system refrigerant.
    3. Recycle, label and store refrigerant.
    4. Evacuate and charge A/C system; add refrigerant oil as required.



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