ASE T7 HVAC (Medium/Heavy Truck) study plan
ASE T7 HVAC (Medium/Heavy Truck) · Give each week a clear focus.
8 weeks · About 6 hours per week
HVAC System Components and Operation
Diagram the full refrigerant circuit from compressor discharge to suction, labeling each component and state change
Explain the function of each major component: compressor, condenser, receiver-drier/accumulator, expansion device, evaporator
Distinguish TXV vs orifice tube systems and identify which components differ
Trace the path of refrigerant and oil through both system types on a hand-drawn schematic
Your checkpoint
Hand-drawn, fully labeled refrigerant circuit schematic for both TXV and orifice-tube systems, with a one-paragraph explanation of each state change
HVAC System Components and Operation & Refrigerant System Diagnosis and Repair
Describe how compressor clutch, condenser airflow, and expansion device failures each affect high- and low-side pressures
Interpret a pressure/temperature chart to convert gauge readings to expected evaporator and condenser temperatures
List the steps of a systematic performance test including ambient conditions and vent temperature expectations
Identify common causes of no-cool, weak-cool, and cycling-compressor complaints
Your checkpoint
Completed pressure-diagnosis table matching at least 6 symptom patterns (both high, both low, high-high/low-low, etc.) to likely causes
Refrigerant System Diagnosis and Repair
Perform leak detection using electronic detector, dye, and soap solution, and rank them by appropriate use case
Explain the procedure for locating and repairing a leak, including evacuation and recharge afterward
Describe how to diagnose a restricted expansion device versus a restricted condenser or line
Outline compressor diagnosis including clutch, reed valve, and internal wear symptoms
Explain moisture/air contamination symptoms and the role of the receiver-drier or accumulator
Your checkpoint
Written diagnostic flowchart for a slow leak from complaint to verified repair, including test order and pass/fail criteria
Electrical/Electronic Controls and HVAC System Diagnosis
Trace the control circuit for compressor clutch engagement from fuse through relay, pressure switch, and PCM
Explain how pressure switches, thermistors, and blower resistors/modules control HVAC operation
Interpret a wiring schematic to locate opens, shorts, and high-resistance connections in an HVAC circuit
Describe how to test a blower motor, blower module, and relay with a DMM and voltage-drop method
Your checkpoint
Completed voltage-drop and circuit-trace worksheet for a simulated no-blower and no-clutch scenario, with the faulty component identified for each
Heating and Cooling System Diagnosis and Repair
Explain coolant flow through the heater core and the effect of blend-door position on outlet temperature
Diagnose no-heat complaints by distinguishing coolant flow, air pocket, blend door, and thermostat causes
Describe heater core replacement considerations including dash removal and coolant refill/bleed
Explain the operation of the A/C evaporator in dehumidification and defrost performance
Your checkpoint
No-heat diagnostic decision tree with at least 5 branches, each ending in a specific test and pass/fail threshold
Heating and Cooling System Diagnosis and Repair & Electrical/Electronic Controls and HVAC System Diagnosis
Diagnose automatic temperature control faults including in-car sensor, ambient sensor, and actuator feedback circuits
Explain blend-door actuator calibration and how to verify door travel and position
Describe cabin air filter, evaporator drain, and blower housing airflow restrictions and their symptoms
Test a blower motor circuit end to end and interpret current draw versus specification
Your checkpoint
Completed ATC fault-isolation worksheet covering sensor, actuator, and control-head faults with the test sequence for each
Refrigerant Recovery, Recycling, and Safety Practices
Explain the recovery, recycling, and recharge sequence and the purpose of each step
Describe refrigerant identification, contamination screening, and the handling of mixed or unknown refrigerant
State the safety practices for refrigerant handling: PPE, ventilation, frostbite and asphyxiation hazards, and cylinder storage
Explain evacuation, vacuum hold testing, and why moisture removal matters
Describe legal and environmental responsibilities for refrigerant containment and recordkeeping
Your checkpoint
One-page recovery/recharge procedure checklist with safety callouts and a vacuum-hold pass/fail criterion
HVAC System Components and Operation & Refrigerant System Diagnosis and Repair & Heating and Cooling System Diagnosis and Repair & Electrical/Electronic Controls and HVAC System Diagnosis & Refrigerant Recovery, Recycling, and Safety Practices
Complete timed practice sets across all five domains and score each domain separately
Re-teach the two weakest domains using your own notes and diagrams
Rehearse pressure-diagnosis and circuit-trace scenarios under time pressure
Review safety and recovery procedures one final time for recall accuracy
Your checkpoint
Scored practice exam summary showing per-domain percentages, with a written remediation note for any domain below 80%
Milestones
Week 2: Can draw both system schematics from memory and correctly predict high/low pressure behavior for 4 of 5 fault scenarios
Week 4: Scores at least 80% on a mixed Domain 1/2/4 practice set and can trace a clutch circuit without notes
Week 6: Scores at least 80% on a mixed Domain 3/4 practice set and completes a no-heat and no-blower diagnosis without reference
Week 8: Scores at least 80% in every domain on a full timed practice exam, with safety/recovery items at 90% or better