545 Hudson Drive, Dorchester, ON N0L 1G5

Your Go-To Destination for Semi Truck AC Repair Near You

At Tubby’s Truck & Trailer, we understand how crucial it is for truckers to have a reliable and efficient air conditioning system, especially during long-haul journeys. In this blog, we will address the common question of why your AC may not be working in your semi, and provide insights into the average time it takes to fix an air conditioner in a truck.

How Does the AC System Work in a Semi Truck?

Understanding how the AC system works in a semi truck can help truckers diagnose issues and appreciate the complexity of this vital component. Let’s delve into the functioning of a typical AC system in a semi truck.

Refrigerant Circulation:

The AC system relies on a refrigerant, usually a chemical compound like R134a or R1234yf, which circulates through various components to facilitate cooling. The refrigerant transitions between liquid and gaseous states to absorb and release heat, providing the cooling effect.


The AC compressor is the heart of the system. Driven by a belt connected to the engine, the compressor’s primary function is to compress the low-pressure refrigerant vapour, increasing its temperature and pressure. This process prepares the refrigerant for the heat exchange in the condenser.


The high-pressure, high-temperature refrigerant vapour leaves the compressor and enters the condenser, typically at the front of the truck. The condenser consists of a series of tubes with fins that facilitate heat dissipation. As the hot refrigerant flows through the condenser, air passing over the fins cools it down, causing it to condense into a high-pressure liquid.

Receiver-Drier or Accumulator:

Depending on the AC system design, the receiver-drier or accumulator acts as a filter and moisture remover. It contains a desiccant that absorbs any moisture in the refrigerant, preventing damage to the AC system. Additionally, it stores excess refrigerant during low cooling demands.

Expansion Valve or Orifice Tube:

After leaving the receiver-drier, the high-pressure liquid refrigerant passes through the expansion valve or orifice tube. These components regulate the flow and reduce the pressure of the refrigerant, creating a pressure drop. The sudden drop in pressure causes the refrigerant to expand rapidly, resulting in a significant temperature decrease.


The cold, low-pressure refrigerant enters the evaporator, which is typically located inside the cabin. The evaporator consists of fins and tubes similar to the condenser but works reversely. As warm air from the cabin blows over the evaporator, heat is absorbed from the air, resulting in cooler air exiting the evaporator and entering the cabin.

Blower Motor and Air Distribution:

The blower motor, powered by electricity, drives air over the evaporator and circulates it throughout the cabin. The blower motor’s speed can be adjusted using AC controls to regulate the airflow and temperature. The conditioned air is distributed through the truck’s vents, providing the driver and passengers a comfortable environment.

Temperature and Pressure Sensors:

Modern AC systems often include temperature and pressure sensors to monitor performance and ensure optimal cooling efficiency. These sensors provide feedback to the AC control module, allowing it to make necessary adjustments to maintain the desired temperature.

By understanding the functioning of the AC system in a semi truck, truckers can appreciate the interplay between these components and better grasp potential issues that may arise. Regular maintenance, prompt repairs, and professional servicing can help ensure a reliable and efficient AC system to keep truckers comfortable on their journeys.

Why Is My AC Not Working In My Semi?

It can be incredibly frustrating when your air conditioning system fails to keep you cool during those scorching summer months. Several factors can contribute to a malfunctioning AC in your semi truck, including:

Refrigerant Issues: Insufficient or leaking refrigerant can lead to poor cooling performance. This can occur due to damaged hoses, seals, or even the condenser. Over time, refrigerant levels naturally decrease, and regular maintenance is necessary to ensure optimal AC performance.

Electrical Problems: Faulty wiring, blown fuses, or damaged switches can disrupt the electrical circuit responsible for your AC’s functioning. Electrical issues can prevent the compressor from engaging or cause inconsistent cooling.

Compressor Failure: The compressor is vital to your truck’s AC system. If it fails, it can result in no cold air being produced. Common causes of compressor failure include oil leaks, clutch problems, or general wear and tear.

Blower Motor Malfunction: The blower motor is responsible for distributing cooled air throughout the cabin. If it malfunctions, you may experience weak airflow or no air. Issues such as a faulty motor, worn-out bearings, or a damaged fan can impede the blower’s functionality.

Clogged Evaporator or Condenser: Over time, the evaporator and condenser coils can accumulate dirt, debris, and grime, obstructing the heat transfer. This can result in reduced cooling efficiency or even a complete system failure.

How Long Does It Take To Fix an Air Conditioner in a Truck?

The time it takes to repair an air conditioner in a semi truck can vary depending on the problem’s extent and the parts’ availability. While minor issues can be resolved within a few hours, more complex repairs may take longer.

Simple maintenance tasks such as refrigerant recharging, replacing fuses, or fixing loose connections can typically be completed within a couple of hours. These tasks may not require specialized parts and can be addressed quickly by experienced technicians.

However, if your AC problem involves more significant repairs, such as compressor replacement or addressing electrical malfunctions, it may take several hours or even a day to complete. In such cases, our skilled technicians at Tubby’s Truck & Trailer will thoroughly diagnose the issue, source the necessary parts, and work efficiently to restore your AC system to optimal functionality.

It’s important to remember that proactive maintenance and regular servicing can help prevent major AC breakdowns and reduce repair time. By scheduling routine inspections and addressing minor issues promptly, you can ensure a longer lifespan for your AC system and minimize downtime on the road.

Choose Tubby’s for AC Repair

When you’re in need of semi truck AC repair near you, Tubby’s Truck & Trailer is the ideal choice. We understand the significance of a reliable air conditioning system, especially for long-haul truckers. Our team of skilled technicians is equipped to handle a wide range of AC problems efficiently and promptly. Don’t let a malfunctioning AC disrupt your journey—reach out to Tubby’s Truck & Trailer today for expert AC repair services.