Many people complain that the air vents in their cars start to blow out hot air when they turn off the heaters. The situation becomes problematic in summer because you need cold air to make the interior comfortable.
Why is my Car Blowing Hot Air When the Heater is Off? Your car can blow the hot air when the heater is off due to using the wrong mode, faulty blend doors, and its actuator. In addition, the issue also comes due to leakage of refrigerants, clogged cooling fans, faulty condensers or compressors, electrical problems, dirty air filters, and when climate control is on.
It is unsafe to drive your car when it is blowing hot air through vents because it also comes due to electrical issues like a blown-out fuse, faulty wiring, and short circuits. You should check the electric switches, relay, and ground wires before moving further.
Use of the wrong mode
Many people face hot air issues due to selecting the wrong mode. The problem comes when you forget to turn on the recirculation mode in your car.
The recirculation mode is present in vehicles that are helpful to make the interior cabin cool while keeping the hot air outside the unit.
The heater system control is beneficial for adjusting the different temperature ranges. In addition, the hot air also comes from the vents because of poor adjustment of the temperature knob.
You can fix the problem by activating the right mode to get cold air rather than hot. For example, turn on the recirculation mode rather than the intake mode.
The recirculation mode activation will help keep the cabin cool by removing hot air. Furthermore, check the temperature knob set to adjust the airflow temperature according to your requirement.
The issue with blend doors
The blend doors are not the door-like structure as their name indicates. Instead, the instrument is an essential component of a car ac unit.
It is helpful to control the flow of warm and cold air. Its primary function is to send air through the heater when you use the heater.
It also passes through the cooler when you select the ac mode in your car. Sometimes the blend doors get stuck in a specific position, and you can face the issue.
The faulty actuator and failure of the motor also cause them to get stuck in one position, and hot air is continuously coming from the vents.
Change the blend door actuator if you have any burning smell from the cabin. The replacement of this instrument is the only solution to fix the above problem.
In addition, these are connected to climate control systems, and you can check their functioning before the replacement procedure.
You can test the climate control system to verify its functioning and go for further procedures.
It is also essential to disengage the battery negative terminal before replacing the blend door actuator from the glove box.
Leakage of refrigerant
Refrigerant is the liquid gas present in the vehicles’ cooling system to absorb the heat and humidity from the interior cabin.
This liquid gas travels in the pipes to keep the air cool and maintain a low temperature. The leakage of refrigerant occurs due to damage in these pipes.
The leakage of hoses occurs due to their old age and corrosive side walls.
Inspect the leakage as soon as possible to fix the problem. It is necessary to take your vehicle to the mechanic so he can inspect the hoses and identify the holes in them.
It is also better to use high-quality sealant and repair the tiny visible holes in the hoses from where the refrigerant is moving.
Moreover, you can also use the tap to fix these holes and decreases the seeping of liquid gas.
Clogged cooling fan
Cooling fans work with condensers to reduce the heat and are present on the front side of the car. This help reduces the temperature of the refrigerant that is moving in hoses.
The dust and debris from the roads clogged them, and they cannot perform their function correctly. In addition, these fans’ motor also worsens and causes malfunctioning.
The blown-out fuse also stops the working of these cooling fans. Fix the issue of the cooling fans to prevent the blowing of warm air from vents.
Check the cooling fan fuse and replace the blown-out fuse with a new one. In addition, you can also take your car to the mechanic to unclog the dust and debris from the cooling system.
You have to replace the whole component in case of damaged motors or actuators. The replacement procedure is difficult and technical.
You need help from an experienced mechanic to do this process.
Failure of condenser
A condenser is a tube-like structure, and its primary function is cool the refrigerant cool and continues the cycle by blowing cool air.
You can feel your car’s interior hot due to the faulty or clogged condenser. Road debris and dirt during driving block these condensers and cause malfunctioning.
The failure of its components, like the breakage of pipes and seals, also aggravates the issue. You cannot repair the condensers of the vehicles.
The pipe and seals of this component are also unrepairable, and you need to replace the whole unit. Remove the refrigerants from the condensers before replacement.
Detach the old one and carefully install the new equipment in the same place.
The compressor is the major component of the HVAC system because refrigerant is circulating in it.
The air vents blow the hot air because faulty compressors do not transfer the antifreeze to the condenser for cooling purposes.
The heat cannot move outside due to the failure of this system. The issue in this part occurs due to electrical failure, fluctuation in the level of refrigerants, blockage of suction lines, and contamination.
You can fix it by lubricating the whole system with high-quality liquid. Regular cleaning is also necessary to make them free from grime and dust.
Moreover, it is also necessary to change the filters for proper air circulation. It is better to check the refrigerant level for its accurate functioning.
Dirt in air filters
The air filters are present in the cabin to filter the dust and small residues from the air and prevent them from entering the system.
The car AC unit cannot effectively maintain the cooling temperature due to dirty air filters. As a result, it puts more pressure on the system and causes overheating.
In addition, the air cannot correctly recirculate, and you can feel the warm air from your car. You can fix it by changing the air filters after some time for their efficient working.
Moreover, you can also gently clean them with bristle brushes and remove the residues from their surface.
Take out the air filters from the cabin for the cleaning procedure.
Climate control turns on
The climate control system is present in all the latest and most luxurious cars to adjust the internal temperature according to weather conditions.
Sometimes vehicles start to blow the hot air while the heater is turned off because the climate control system is on.
You can feel the warm air coming out from the vents because of the temperature setting and functioning of the climate control system.
You can fix the issue by activating your car’s recirculation or cooling mode.
The activation of recirculation mode becomes beneficial because it stops the hot air entry from the outside that is blowing through the air vents.