How the A/C System Affects Your Vehicle’s Heating System

A Car’s Defroster Wasn’t Working… It was the Freon’s Fault

Scott recently brought in his 2009 Honda Pilot in for service. His concern was that the defroster in his SUV wasn’t working properly.

The trained technicians verified Scott’s concern, and then performed a visual inspection of the entire cooling system as the first step in the troubleshooting process. All the main HVAC components looked good and everything seemed fine from a visual standpoint. The next step was to perform a ‘pressure check’ of the cooling system, which also didn’t offer any clues as to why the defroster wasn’t working right.

It was at that time that the technician at Milito’s opted for some out-of-the-box thinking. Relying on his experience and knowledge of automotive systems, the technician then performed a check on the A/C system, referred to as an ‘evac and recharge’.

Well, it turned out that the A/C system was low on freon. After recharging the system, the defroster began working properly! What the heck?

The Air Conditioning System Assists your Car’s Defroster.

An automotive air conditioning system affects heating by utilizing the same system to provide both cool air and warm air to the cabin of the vehicle.

The system works by using a refrigerant to absorb heat from the cabin, which is then expelled to the outside of the vehicle.

During the cooling process, the refrigerant is compressed and sent through the condenser where it releases heat to the outside. The now-cooled refrigerant then flows through an expansion valve, causing it to rapidly expand and cool even further.

This cooled refrigerant is then sent through the evaporator where it absorbs heat from the cabin air, resulting in cool air being circulated throughout the cabin.

Therefore, an automotive air conditioning system is designed to provide both cooling and heating to the cabin of the vehicle using the same system.

The system is able to switch between these modes by using a combination of components such as the compressor, condenser, expansion valve, and heater core to regulate the temperature of the air being circulated in the cabin.

How the Air Conditioning System Affects a Vehicle's Heating System - MilitosAutoRepair.com

So How Does it Actually Work?

The automotive air conditioning system also plays a crucial role in the defrost function of a vehicle. The defrost function is used to remove moisture and condensation from the windows of the vehicle, which can obstruct the driver’s view and create unsafe driving conditions.

When the defrost function is activated, the air conditioning system is turned on, but instead of providing cool air to the cabin, it is used to dehumidify the air. The air is passed over the evaporator, which is usually located inside the dashboard, and the moisture in the air is condensed onto the evaporator. This dehumidified air is then blown onto the windows to remove any condensation or moisture.

In addition, the air conditioning system also helps to defrost the windows by providing warm air. When the defrost function is activated, the air conditioning system switches to heat mode, and the heater core is used to provide warm air to the cabin. This warm air is also blown onto the windows to help remove any condensation or moisture that has accumulated on them.

Therefore, the air conditioning system plays an important role in the defrost function of a vehicle by dehumidifying the air and providing warm air to remove any moisture or condensation from the windows. It is essential to keep the air conditioning system well-maintained to ensure that it is working properly and providing optimal defrosting performance.

Will the Defrost Work if the A/C System Isn’t Working?

The defrost function of a vehicle may not work properly if the air conditioning system is not working. As mentioned earlier, the air conditioning system is used to dehumidify the air, which is essential for the defrost function to work effectively.

If the air conditioning system is not working, the air passing over the evaporator will not be dehumidified, and the moisture in the air will not be condensed onto the evaporator. This means that the air blown onto the windows will still contain moisture, which can result in reduced effectiveness of the defrost function.

However, if the defrost function is activated while the air conditioning system is not working, the warm air from the heater core may still be blown onto the windows to help remove any moisture or condensation. But without the dehumidifying capability of the air conditioning system, the effectiveness of the defrost function will likely be reduced.

Therefore, it is important to ensure that the air conditioning system is working properly to maximize the effectiveness of the defrost function. Regular maintenance and inspections of the air conditioning system can help identify and address any issues that may affect its performance.

Get Your Car Ready for Any Winter at Milito’s Auto Repair!

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