Developed specifically for Professional Medium/Heavy Duty Truck Technicians, this training series covers topics in all of the key skill areas. Choose from interactive training in Brakes, Electricity and Elextronics, Preventive Maintenance, Suspension and Steering, Heating, Ventilation, and Air Conditioning, and Drive Train.
Online ASE Test Preparation
Prepare for your ASE Exams Online Medium/Heavy Duty Truck Series (T1 - T8) Technician Test Preparation (TTP) - Medium/Heavy Truck Series is the ideal way to gain the expertise required to pass the T1 through T8 ASE exams.
We have a 2010 Prostar that has problems with the airflow coming out the vents while going down the highway. He will be going down the highway and the airflow will reduce to almost nothing. When the driver comes to a stop, it will start back up again. We have verified function of all of the actuators and ductwork.The blower motor also doesn't reduce speed. Anybody have any tips/experience with this problem? VIN 3HSCUAPR4AN272126
No experience with that exact problem on that exact truck, but I have few suggestion or questions to ask yourself. 1. Could the module on the blower motor be going out when it gets hot? 2. You said heater, but could the unit also be in defrost mode and the evaporator is freezing up from the A/C clutch staying on due to faulty inlet and outlet temperature readings. You will need to use dimaond logic builder to look at those 2 temperatures. If the evaporator freezes it will restrict air flow. In the winter time there is a larger delta between outside ambient temperature to condensor temperature, so the system can pull heat out of the system much quicker going down the highway versus when the unit stops.
Freightliners use to have that problem all the time with the Blend air system, winter or summer. Driver complaint no air flow. The HVAC relay would stick close and the system could not cycle the A/C clutch to prevent freeze up. You could indentify this by turning on the ignition switch and the compressor clutch would be engaged. On a blend air system the clutch should not be enaged with just key on, a parameter that needs to be seen by the AC module is engine rpm above 500 rpm for 15 seconds.
I belive you can do this same check on a ProStar, the A/C clutch output is direct from the Body Controller to the clutch and it does need to see engine rpm for engagement. Hope this helps with some of the troubleshooting proccess.
ASE Test Preparation Medium/Heavy Duty Truck Series: T1-T8
This updated fourth edition has been completely updated to provide the most current ASE test preparation material for Medium/Heavy Duty Trucks available anywhere. Each book in the series provides valuable preparation for Medium/Heavy Duty Truck Technicians seeking certification in one or more of the ASE Medium/Heavy Duty Truck Technician Certification areas. Readers are afforded scores of opportunities to ascertain their knowledge of critical concepts, through the extensive array of sample problems, ASE-style exams, and competency-specific test questions required for certification by ASE. Refresher materials, helpful test-taking strategies, and thorough explanations round out this comprehensive preparation package