MTST VI: HEATING, VENTILATION, AND AIR CONDITIONING (HVAC)

A. General
MHT6A001 Research vehicle service information, including refrigerant/oil type, vehicle service history, service precautions, and technical service bulletins.
MHT6A002 Identify heating, ventilation, and air conditioning (HVAC) components and configuration.
MHT6A003 Use appropriate electronic service tool(s) and procedures to diagnose problems; check, record, and clear diagnostic codes; interpret digital multimeter (DMM) readings.
MHT6A004 Diagnose heating and air conditioning problems; determine needed action.
MHT6A005a Identify refrigerant type; test for contamination; select and connect proper gauge set/test equipment; record temperature and pressure readings.
MHT6A005b Identify refrigerant type; test for contamination; select and connect proper gauge set/test equipment; record temperature and pressure readings.
MHT6A005c Identify refrigerant type; test for contamination; select and connect proper gauge set/test equipment; record temperature and pressure readings.
MHT6A006 Perform A/C system performance test; determine needed action.
MHT6A007 Perform A/C system leak test; determine needed action.
MHT6A008 Inspect condition of refrigerant oil removed from A/C system; determine needed action.
MHT6A009 Determine oil and oil capacity for system application and/or component replacement.
B. Refrigeration System Components
MHT6B001 Inspect, remove, and replace A/C compressor drive belts, pulleys, and tensioners; verify proper belt alignment.
MHT6B002 Check A/C system operation including system pressures; visually inspect A/C components for signs of leaks; check A/C monitoring system (if applicable).
MHT6B003 Inspect A/C condenser for airflow restrictions; determine needed action.
MHT6B004 Inspect, test, service, and/or replace A/C compressor and clutch assembly; check compressor clutch air gap; determine needed action.
MHT6B005 Inspect, service, and/or replace A/C system hoses, lines, fittings, O-rings, seals, and service valves.
MHT6B006 Inspect, remove, and/or replace receiver/drier or accumulator/drier.
MHT6B007a Inspect, remove, and/or replace expansion valve or orifice (expansion) tube.
MHT6B007b Inspect, remove, and/or replace expansion valve or orifice (expansion) tube.
MHT6B008 Inspect evaporator housing water drain; perform needed action.
MHT6B009 Diagnose A/C system conditions that cause the protection devices (pressure, thermal, and/or control module) to interrupt system operation; determine needed action.
MHT6B010 Determine procedure to remove and reinstall evaporator.
MHT6B011 Determine procedure to inspect and/or replace condenser.
C. Heating, Ventilation, and Engine Cooling Systems
MHT6C001 Inspect engine cooling system and heater system hoses and pipes; determine needed action.
MHT6C002 Inspect HVAC system heater ducts, doors, hoses, cabin filters, and outlets; determine needed action.
MHT6C003 Identify the source of A/C system odors; determine needed action.
MHT6C004 Diagnose temperature control problems in the HVAC system; determine needed action.
MHT6C005 Determine procedure to remove, inspect, reinstall, and/or replace engine coolant and heater system components.
D. Operating Systems and Related Controls
MHT6D001 Verify HVAC system blower motor operation; confirm proper air distribution; confirm proper temperature control; determine needed action.
MHT6D002 Inspect and test HVAC system blower motors, resistors, switches, relays, wiring, and protection devices; determine needed action.
MHT6D003 Diagnose A/C compressor clutch control systems; determine needed action.
MHT6D004 Diagnose malfunctions in the vacuum, mechanical, and electrical components and controls of the HVAC system; determine needed action.
E. Refrigerant Recovery, Recycling, and Handling
MHT6E001 Understand correct use and maintenance of refrigerant handling equipment.
MHT6E002 Understand how to identify A/C system refrigerant; test for sealants; recover, evacuate, and charge A/C system; add refrigerant oil as required.
MHT6E003 Understand how to recycle, label, and store refrigerant.