Onsite Truck & Equipment Repair Blog

Complete Guide: Truck HVAC System Maintenance and Repair



The technology-driven nature of the transportation industry has compelled drivers to seek out more comfortable conditions as they drive long hours. The off-road construction and agricultural industry requires a great amount of concentration from the driver, but must be able to withstand extreme weather conditions as well. Many trucks come equipped with heavy-duty HVAC units capable of extracting and distributing heat and cool air, but these systems can be susceptible to damage from the rugged terrain and adverse weather conditions.

Battery-powered heating, ventilation, and air conditioning (HVAC) systems help fleets deal with cab climate control, by providing climate control to the truck cabin while the truck is parked.

They can be powered by a set of batteries on the tractor or come with a plug-in capability for battery charging and/or operation while connected to an electrical power source. They are also called battery APUs and battery EPUs.

Battery-powered HVAC systems generally use lead-acid batteries; however, lithium-ion and nickel metal hydride batteries are also available. Lithium-ion and nickel metal hydride batteries may be better suited for lower temperatures on some trucks because their low discharge rate enables them to provide quiet cooling for up to eight hours or more without recharging.

The electrical power that drives both types of systems is generated by an internal combustion engine, such as a diesel or natural-gas powered generator, which is located outside of the truck cab and produces emissions. Some manufacturers use electric motors to drive the system and eliminate emissions altogether; these systems are called "battery zero emissions units" (BZEUs). These BZEUs may be powered by a plug-in connection or a small, on-board generator.

These systems also require maintenance and periodic inspections, such as cleaning or replacing filters. If fleets decide to add a battery APU or BZEU, they should check with their truck or engine manufacturer before buying one to ensure that the installation and operation of the unit does not void any warranty. They should also consider maintenance and warranties offered by suppliers; while the systems may be affordable, upkeep and warranties can add to operating expenses.

Contingent on the environment where you drive your truck, it may be taxing for your heating and cooling system to suit all of your needs without failure. This is why looking after your vehicle's HVAC systems is so pivotal.

Signs For Maintenance

There are several signs for operators to watch out for that indicate that the APU needs to be serviced or replaced.

Filters, coils, and fins on an air conditioner require continual maintenance for the unit to operate effectively and efficiently throughout its lifespan. When your air conditioner is not maintained, it will lose efficiency and overall risk will rise over time. The following are some simple signs to be vigilant of that may be indicative that your truck's HVAC needs to be looked at.

Temperature Gauge Doesn't Work

If the temperature gauge inside of the truck is not turning on, then it is time to get the APU checked out because this could mean there is a problem with an electrical system.

Clicking Sound

Another sign for operators to watch for is a clicking sound from the engine. This means there might be a problem with the generator and could result in overheating if left alone.

Squeal Or Whistling Noise

A high pitched squeal or whistling noise coming from the unit means that it needs maintenance as well. If the blades on either side of the drive belts are worn, then they need replacement.

Any of these or similar occurrences mean that it is likely time to call a service professional for HVAC inspection or repair. Without servicing or replacement, these problems will only get worse over time and result in an unsafe vehicle.

The Importance Of HVAC Maintenance

It is important for truckers to take care of their vehicles properly because these trucks will be used in ways that many other vehicles are not. These vehicles spend a lot of time on the road, making them more susceptible to wear and tear.

Operators who fail to maintain their vehicles properly might find that they are not as reliable as they should be. This could cause problems for drivers on the road because it can end up putting other people in danger. It is important for all truckers to make sure their vehicles are always in good operating condition.

Mobile generators, such as the diesel-fueled APU and BZEU discussed in this article, also need routine service and maintenance, especially if they're part of a truck's engine and air system. Drivers can't expect these onboard units to perform reliably without proper care.

The main issue with these systems is that they are very complex, and problems can occur if they're not maintained properly. These devices turn the engine's power into electric current for use in heating, air conditioning, or electronics throughout the truck.  If these respective systems are not operating properly, safety and comfort for the driver and passengers could be compromised.

With winter approaching fast, it is important to keep your heating system in check before facing freezing temperatures on the road.

General Maintenance For Trucks, Including HVAC Systems

It is important to keep your truck in good condition so that it will be safe for everyone on the road. This could be done with regular servicing.

Preventive maintenance for trucks involves checking every part of the vehicle's engine, transmission, and other systems through various tests to ensure they are working. This type of checkup will help you get more out of your vehicle, reduce the chances of it breaking down, and increase the lifespan.

There are also some things that drivers can do for HVAC maintenance, but only to a certain extent. While some maintenance issues might be easy for drivers to handle themselves, it is always best to have a qualified engineer complete work on the truck's HVAC system.


If you have any problems with your air conditioner, heater, or other onboard systems, contact a service professional for assistance right away. The earlier they find and fix any issues, the better you and your vehicle will be in the long run.

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