How does the ventilation system work?

How does the ventilation system work?
Experienced mechanics share their insights in answering this question :
Sometimes you don’t want the heat or the air on in the car. The ventilation system is designed to circulate fresh air from outside the car into the cabin. To use this system, follow these steps:

Turn the temperature control dial to cold.
Turn off the air conditioner if it’s on.
Change the mode to fresh air.
Adjust the fan speed to your preference.
Adjust the vents to your preference.

How to Identify and Fix Common car Problems ?

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Changing the fuse can solve the problem, or it can simply be a blown a fuse. There is no difficulty in replacing it. If it works intermittently, there may be a problem with your air/heat. When the blower motor operates in one mode and does not in another mode, then you may need to replace the blower motor resistor.
The most common reasons a Honda Accord ac isn`t working are a refrigerant leak, an electrical climate control issue, or a problem with the air conditioning compressor. You may not realize there`s a refrigerant leak until the air conditioner stops blowing cold.
With the fan on, push the A/C button to operate the air conditioning. The indicator light will come on. Push the button again to turn off the air conditioning. When the button is pushed, the indicator light will go on and outside air will be circulated inside the car.
The blower motor is responsible for sending air through the vents of your car. Over time, blower motors can become damaged, or completely fail. In which case, air will no longer come out of your vents.
If you feel no air is blowing from vents in your house, vent blockage is most likely to be the issue. You might be blocking your air vents unknowingly; a piece of furniture might be in front and blocking the airflow, or you might have closed some vents on a chilly day and forgotten to open them again.
If your car`s air conditioning isn`t blowing cold air at all (or it tries, then turns warm), you could have a clogged expansion valve, a faulty compressor clutch, a leak, or a malfunctioning fuse in the system.
Nine times out of 10, weak airflow is caused by a clogged up cabin air filter. Over time, this filter catches all dirt and debris, which can build up and slow or stop the flow of air. It`s typically located under the dash on the passenger side or inside the glove box and should be cleaned or replaced regularly.
The air-conditioning system in a car works by manipulating refrigerant between a liquid and a gaseous state. As the refrigerant changes states, it absorbs heat and humidity from the vehicle and allows the system to give off cool, dry air.
Cool Mode. Commonly symboled with a snowflake – the cool mode is basically the default mode of most AC units. When you use this mode, your air conditioner starts by turning on the compressor to push cold air into the room.
However, when the car is moving, this might not look like an issue as the outside air will go through the engine. But when the car is not moving, there is no air from outside to cool the engine; therefore, the AC doesn`t work when the car is not moving.
You cannot run the AC without the engine running. The air conditioner compressor and clutch are operated by the serpentine belt that runs your other accessories (your alternator, for instance). If the engine isn`t running, then the belt isn`t turning. That means your air conditioner`s not actually on.
Fresh, unpolluted air enters your home through the intake vents placed at the low points of your roof. Air expands and rises as it becomes warmer, so the hot, moisture-filled air rises and escapes through the exhaust vents placed at the height of the roof.
The HVAC system will fill the supply plenum with heated or cooled air, which then is sent through the ductwork of the system. When this heated or cooled air enters a room, it pushes the already-present air out of the room into another set of ducts. These ducts deliver this returned air to the return plenum.
If you are looking at a duct that is coming off the furnace and going straight up like it is going to the upstairs, and the wing is in the same direction as the duct, it is open. If the wing is in the opposite or vertical position to the ductwork, then the damper is closed.
A runny nose and sneezing can happen too. If poor ventilation continues to be a problem, you might experience headaches, fatigue, and shortness of breath. Dizziness is a common symptom too. All of these symptoms are magnified in sensitive groups who have respiratory diseases or asthma.
A second reason for the air conditioning unit to suddenly prefer blowing warm air may be because the compressor itself has gone bad. The main function of the compressor is to pressurize the contents in the refrigerant, and then pump it throughout the necessary components of the AC.
The most common causes of broken air conditioning are leaks or compressor issues. If your air is blowing cool but not cold, the problem could be a clogged filter, cooling fan problem, radiator trouble, or it could simply be that you need to recharge your AC.
If you are experiencing weak airflow from vents in the house, check whether it is happening only in one vent or multiple vents. In case only one vent shows the problem, you may be having a problem with a disconnected or leaky duct, a crushed duct flex or a closed damper.
If the heater isn`t blowing hot air at you when you turn the system on, the blower fan might have a problem. Either it`s not getting electrical power or, more likely, the motor itself has simply burned out. A blower motor in an older vehicle is likely to burn out over time, and may need replacement.
A fan clogged by dirt, a stuck wheel, broken motor, or a loose fan belt are all common problems that reduce the amount of airflow you feel coming from your vents.
If the heater isn`t blowing hot air at you when you turn the system on, the blower fan might have a problem. Either it`s not getting electrical power or, more likely, the motor itself has simply burned out. A blower motor in an older vehicle is likely to burn out over time, and may need replacement.
If the heater isn`t blowing hot air at you when you turn the system on, the blower fan might have a problem. Either it`s not getting electrical power or, more likely, the motor itself has simply burned out. A blower motor in an older vehicle is likely to burn out over time, and may need replacement.
Blocked Vent or Duct

A reasonably simple explanation for poor airflow in a particular area of your house could be that you have a blockage in an air duct near that area. If the problem affects one room, the vent in that room could have some blockage.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Just replaced head gasket, changed crack sensor new plugs. The check engine light is on, but dim, the only other light that the dash is a normal battery indicator. The fuel pump is not running when switch is turned on, the power windows don’t work, it turns over but not firing. It’s like only one part of the system is working. Also the heater fans work even if the switch is off.
ANSWER : I would first look at the diagnostic trouble codes. Those codes are available because the check engine light is on. If the fuel pump is not running (momentarily) at key on, that fault alone will prevent the car from starting as there will be no fuel pressure. Pump output and pressure can be directly tested and you can also check for electrical power to the pump. To find out why the engine will not run, the recommended diagnostic is a no start diagnostic. If you request that service, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Windshield wipers stopped working. They’ll suddenly stop working then suddenly start working again. Has been happening for a week.
ANSWER : The problem you are describing likely stems from an intermittent electrical fault in the wiper circuit. The windshield wiper system uses a small electric motor to move the wiper arms that you see on the windshield. That electric motor is controlled through a switch, relay, fuse, and wiring. One, or more, of those electrical components has failed although it is also possible that the mechanical arms are binding (seized, if the lubricant has dried out) thus causing the electric circuit to the motor to overload. Regardless of the underlying fault, if you request a non functioning wiper diagnostic/repair, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

My dash board don’t work my front light work when I change my light into high beam and my back window won’t go down
ANSWER : As unfortunate as it is, your vehicle would be considered flood damaged. Diagnosing electrical problems in a flood damaged vehicle is nearly impossible. This would take many hours or even days to determine which wiring harnesses and circuits have been affected. Then nearly all of the wiring under the dash would likely require replacement as well as many sensors and switches. On a BMW vehicle, the amount of wires and switches are likely more than that of a lower end vehicle. Due to the inefficiency in cost, you would likely be able to purchase another BMW like yours for less than what it would cost to fix your car. Many insurance companies would consider this type of damage to total out the vehicle unfortuantely.

My AC does not always work. If I fiddle with the blower knob I can ususally get it to work on the lowest setting.
ANSWER : Hi There,
It sounds like you may have a faulty blower motor resistor. The highest speed setting may still work because in most cars in the highest fan speed settings the current bypasses the blower motor resistor. In some cars, if the resistor is failed, the fan may stop working completely. Another reason a blower motor resistor may fail is when the blower motor has a mechanical problem or when a foreign object jams the blower motor fan blade and prevents it from spinning freely. This leads to increased current through the resistor and causes it to overheat and fail. I would suggest having an expert from YourMechanic come to your location to diagnose your system to determine what may be causing the fan not to work properly.

All dashboard lights and tail lights do not work after driving through a lot of snow. Headlights work. And brake lights work.
ANSWER : Hello. We’ll be happy to help you. There are a few things that I recommend checking to discover why your lighting system is malfunctioning. The headlight dimmer switch should be checked. Along with the wiring harness above the right front tire behind the fender well cover. Also
the main fuse under the hood should be inspected because other people with your particular vehicle have had similar lighting issues if that fuse goes bad. It will be a great idea to check the rest of the fuses in that area too while checking the main fuse. Once the fuses are checked inside of the main fuse box then I would check the fuses inside of their interior fuse box. The interior fuse box should be located on the driver side of the dashboard near where your legs would be. If you need more assistance with repairing your vehicle please keep in mind that our organization provides Mobile Mechanics who can help you diagnose and repair your vehicle, all at competitive rates.

Dash, Tail/brake, dome, trunk, glovebox, and door lights won’t work, dash doing weird things.
ANSWER : Hi there. Sure would appear a lot is going on electrically all at once. This could be, a problem in the PDC (power distribution center). The PDC is typically located under the hood and contains numerous fuses and relays. I don’t believe any one fuse will resolve all of the electrical issues. There is a possibility, it is not a power supply issue. It may be, the result of a poor electrical ground common to the inoperative components. Proper circuit testing should be performed. This would confirm the cause of multiple electrical failures. I recommend having your vehicle’s electrical problems be diagnosed and repaired by a certified technician, such as one from YourMechanic.

How does the ventilation system work?
ANSWER : Sometimes you don’t want the heat or the air on in the car. The ventilation system is designed to circulate fresh air from outside the car into the cabin. To use this system, follow these steps:

Turn the temperature control dial to cold.
Turn off the air conditioner if it’s on.
Change the mode to fresh air.
Adjust the fan speed to your preference.
Adjust the vents to your preference.

Okay so when I turn my lights on at night my brake lights do not work, when I don’t have my lights on they work fine.
ANSWER : Hi there. Based on your inquiry, it’s highly probable that you have a damaged light switch or some electrical fault inside the turn signal relay. However, it’s also possible that the brake switch above the brake pedal could also be the source of your problem. Due to the fact that multiple electrical components might be causing this issue, it’s a smart idea to first have a professional mobile mechanic complete a brake lights are not working inspection, so they can determine what’s causing all of these issues and recommend the right repairs.