Automotive Air Conditioning and HVAC Diagnostics Master Course

01 AH01 - HVAC Foundations and Diagnostic Mindset

• AH01-L01 – What Automotive HVAC Actually Does
• AH01-L02 – Diagnostic Mindset: Complaint, Context, and Verification
• AH01-L03 – Reading a Basic Refrigeration Schematic Without Guessing

02 AH02 - Refrigerants, Oils, Safety, and Compliance

• AH02-L01 – Refrigerant Families, Service Fittings, and Compatibility Logic
• AH02-L02 – PAG, POE, Oil Balance, and Contamination Consequences
• AH02-L03 – Refrigerant Recovery Safety, Legal Boundaries, and Stop-Work Rules

03 AH03 - Refrigeration Physics and Pressure-Temperature Logic

• AH03-L01 – Pressure, Temperature, and Phase Change in Automotive A/C
• AH03-L02 – Latent Heat, Sensible Heat, Humidity, and Why the Cabin Feels Wrong
• AH03-L03 – Why Charge by Pressure Alone Creates False Conclusions

04 AH04 - System Architectures and Refrigerant Flow Paths

• AH04-L01 – CCOT Systems, Orifice Tubes, and Accumulator Logic
• AH04-L02 – TXV, Receiver-Drier, and Variable Flow System Logic
• AH04-L03 – Variable Displacement and Modern Multi-Zone Layouts

05 AH05 - Core Components I: Compressors and Lubrication

• AH05-L01 – Compressor Families, Clutch Logic, and Pumping Principles
• AH05-L02 – Oil Circulation, Oil Starvation, and Debris Pathways
• AH05-L03 – Weak Compressor, Control Valve Fault, or Wrong System State?

06 AH06 - Core Components II: Condensers, Evaporators, and Heat Exchange

• AH06-L01 – Condenser Efficiency, Subcooling Behavior, and Airflow Dependence
• AH06-L02 – Evaporator Performance, Dehumidification, and Icing Logic
• AH06-L03 – Cabin Filter, Airflow Restrictions, and Fake Refrigerant Complaints

07 AH07 - Core Components III: Expansion Devices, Driers, and Restrictions

• AH07-L01 – Orifice Tube Debris, Starvation Patterns, and Flow Restrictions
• AH07-L02 – TXV Superheat Control and Failure Mode Interpretation
• AH07-L03 – Moisture, Desiccant Failure, and Intermittent Ice Restrictions

08 AH08 - Air Distribution, Blend Doors, and Cabin HVAC Hardware

• AH08-L01 – HVAC Box Architecture, Mode Paths, and Cabin Air Routing
• AH08-L02 – Blend Doors, Recirculation Doors, and Actuator Failure Patterns
• AH08-L03 – Heater Core Influence, Temp Split Complaints, and One-Side Warm Faults

09 AH09 - Electrical Foundations for HVAC Diagnostics

• AH09-L01 – Voltage, Current, Resistance, and Load in HVAC Circuits
• AH09-L02 – Relays, Fuses, Grounds, and Voltage Drop Testing
• AH09-L03 – Sensors, Thermistors, Pressure Transducers, and PWM Control

10 AH10 - Climate Logic, Modules, and Communication Strategy

• AH10-L01 – Manual HVAC vs Automatic Climate Control Logic
• AH10-L02 – Compressor Inhibit Logic, Anti-Ice Strategy, and Permission Chains
• AH10-L03 – CAN / LIN Communication Between HVAC, PCM, BCM, and Fan Controllers

11 AH11 - Service Workflow and Shop Discipline

• AH11-L01 – Complaint Interview, Intake Discipline, and Baseline Documentation
• AH11-L02 – Pre-Service Inspection, Machine Hookup, and Recovery Workflow
• AH11-L03 – Post-Service Validation, Documentation, and Comeback Prevention

12 AH12 - Baseline Performance Testing and Data Interpretation

• AH12-L01 – Static Pressure, Ambient Context, and What Static Readings Cannot Prove
• AH12-L02 – Running Pressures, Vent Temperatures, and Line Temperature Reasoning
• AH12-L03 – Building the First Fault Hypothesis Without Guessing

13 AH13 - Cooling Complaint Diagnostics

• AH13-L01 – No Cooling at All: First Differentiation Paths
• AH13-L02 – Weak Idle Cooling, Good Highway Cooling, and Airflow vs Charge Logic
• AH13-L03 – Starts Cold Then Fades: Icing, Control, and Heat-Soak Interpretation

14 AH14 - Pressure Pattern Analysis and Flow-State Diagnosis

• AH14-L01 – Low-Low / Low-High Patterns and What They Really Suggest
• AH14-L02 – Low-Low / High-High and Restriction vs Heat-Rejection Logic
• AH14-L03 – High-Low / High-High Patterns, Equalization Clues, and Misreads

15 AH15 - Electrical and Control Fault Isolation

• AH15-L01 – Compressor Clutch Not Engaging: Circuit, Logic, or Strategy?
• AH15-L02 – Pressure Sensors, Cooling Fans, and False HVAC Conclusions
• AH15-L03 – Blower, Actuator, and Intermittent Electrical Fault Logic

16 AH16 - OEM Scan Tool and Bidirectional HVAC Diagnostics

• AH16-L01 – Generic OBD vs Body/HVAC Module Access
• AH16-L02 – Reading PIDs, Commanding Fans and Doors, and Calibration Workflows
• AH16-L03 – When Scan Data Overrides Gauge Assumptions

17 AH17 - Leak Detection, Vacuum Integrity, and System Sealing

• AH17-L01 – Oil Trace Inspection, UV Dye, and Electronic Leak Detection
• AH17-L02 – Nitrogen Pressure Testing, Vacuum Limits, and Evaporator Leak Strategy

18 AH18 - Hybrid and EV HVAC Systems

• AH18-L01 – Electric Compressors, POE Oil, and Why EV A/C Is Different
• AH18-L02 – Battery Cooling, Chillers, Heat Pumps, and Thermal Management Integration
• AH18-L03 – High-Voltage Boundaries, Lockout Logic, and Diagnostic Escalation Rules

19 AH19 - Advanced Cases, Capstone Diagnostics, and Professional Release Logic

• AH19-L01 – Advanced Case Studies: No Cooling, Intermittent Cooling, and False Diagnoses
• AH19-L02 – Final Diagnostic Method, Repair Recommendation, and Customer Trust

20 CAPSTONE - Integrated HVAC Diagnostic Cases and Professional Release

• Capstone Final Assessment and Professional Release Logic