ASE T7 HVAC (Medium/Heavy Truck) case studies
ASE T7 HVAC (Medium/Heavy Truck) · Put your knowledge to work in context.
The ASE T7 certification is a professional credential for technicians who service heating, ventilation, and air conditioning systems on medium- and heavy-duty trucks. It signals that a technician can diagnose and repair climate-control systems on commercial vehicles, where cab comfort, defroster performance, and reliable refrigerant handling are both a driver-safety concern and a maintenance cost issue. The ASE T7 HVAC (Medium/Heavy Truck) case studies are 5 cases and about 3,132 words.
1Intermittent Cooling on a Route Truck With a Cycling Clutch
A 2019 Class 7 route truck with a 3-zone HVAC system comes in during a 95°F afternoon. The driver reports that cold air fades after 20–30 minutes of highway driving, then returns after a 10-minute stop.
667 words, about 3 min2No Cold Air After Evacuation and Recharge - Moisture and Leak Judgment
A 2016 medium-duty truck with automatic climate control had its compressor replaced at another shop three weeks ago. The customer returns with poor cooling and a musty smell.
630 words, about 3 min3Blower Motor Inoperative on One Speed - Electrical Diagnosis
A 2018 heavy truck with a 4-speed manual HVAC blower and a separate A/C request switch has no blower operation on any speed, but the A/C compressor engages when requested. The blower fuse is intact.
644 words, about 3 min4Heater Performance Complaint - Coolant Flow vs. Air Door
A 2015 medium-duty truck with a 6-cylinder diesel comes in with a heater complaint: lukewarm air at best from the dash vents, worse at idle, slightly better on the highway. Engine coolant temperature gauge reads normal (about 195°F) and the engine reaches operating temperature.
598 words, about 3 min5Recovery Machine Performance and Refrigerant Handling Judgment
A shop's R-134a recovery machine has been in service for two years. A technician is recovering a 3-lb charge from a truck and notices the recovery is very slow; the machine's low-side gauge pulls down to 10 inHg vacuum but the scale shows only 1.5 lb recovered after 15 minutes.
593 words, about 3 min