Your truck’s Heating, Ventilation, and Air Conditioning System (HVAC) are more than just a heater and air conditioner. It also includes the air filter, evaporator coil, blower motor, housing, and ducting.
When there’s a problem with one of these parts, your truck can no longer deliver enough heat or cold air to keep you comfortable. You may also notice that airflow is weak or that some interior vents aren’t working at all.
The automatic temperature control system will not work if one of its components is broken. It includes the blend door, which is essentially an internal flap that controls how much hot or cold air comes into your cab.
This can be especially dangerous if you drive in a colder climate because your defrosting system can no longer function properly, leaving you with fogging windows.
The fuel economy will also decrease because your engine is working harder to generate enough heat for comfort.
Common HVAC Problems & Solutions
The most common problem with the automatic temperature control system is a broken blend door linkage. This can be repaired or replaced depending on how badly it was damaged or if the manufacturer has recalled the part itself.
Your mechanic may also have to replace a faulty AC fan motor because it will not run without one. The wiring might be burnt out as well, which means that your entire dashboard will have to be removed for repair.
If there’s no air flow coming out of your vents at all, it might be that the resistor or blower motor is broken. The resistor cools the AC system to prepare it for the climate of your destination, while the blower motor blows hot or cold air into the cab.
Replacing either one will probably require removing most of your dashboard, so it’s a complex fix regardless of whether you do any parts shopping beforehand.
Frequently Asked Questions
The most common signs include a noticeable decrease in cooling or heating performance, weak or non-existent airflow from the vents, or strange noises like rattling or clicking when the system is active. Other indicators are unpleasant, musty odors coming from the vents or water pooling on the passenger-side floor, which can signal a drainage problem. Any of these symptoms warrant a professional inspection to maintain driver comfort and safety.
The most frequent cause of an A/C system blowing warm air is a low level of refrigerant, which is typically the result of a leak somewhere in the system. Other potential causes include a failing A/C compressor, a clogged condenser, electrical issues with sensors or relays, or a malfunctioning cooling fan. A proper diagnosis is required to identify the exact cause and perform a lasting repair.
If your system is running but little to no air is coming from the vents, the issue is often a severely clogged cabin air filter that is restricting airflow. Another common cause is a failed blower motor or a faulty blower motor resistor. In some cases, it could also be a blown fuse or a mechanical issue with the blend doors that direct airflow within the dashboard.
We recommend a complete HVAC system inspection and performance check at least once a year. The ideal time for this service is in the spring, before the high-demand summer season begins, to ensure your air conditioning is ready for the heat. Regular checks are a vital part of preventative maintenance that can help you avoid unexpected failures and ensure a comfortable and safe driving environment year-round.
Schedule Semi Truck Service at Inland Kenworth
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