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18

I can't give you numbers or calculations without some work, but I can tell you than energy is never free. Cars have an A/C compressor that is mechanically driven by the engine because this is the easiest way to get the job done in a typical consumer car. An A/C compressor actually takes a huge amount of energy to operate. In fact a central A/C unit for a ...


15

You're meant to. In fact, in older cars, it was automatic when redirecting air to the window defroster. On this GM control, the far right position would activate the A/C compressor. Almost always, it is a cold, wet day, and you have both sliders all the way to the right. The pass across the activated A/C coils dries out the air, because of the way ...


13

Well, Teslas (and presumably other all-electric cars) have A/C so it's not impossible, but A/C takes a fair amount of power. On the other hand, Teslas store a lot of energy. The A/C is something like 2.4kW which is about 8,000 BTU/h or about 3HP. So using an electric motor on a conventional car might give you a few more HP briefly, but the alternator has ...


13

In a word No, not even close. Some are all mechanical, some vacuum, some completely electronic. some are combined with the infotainment device (radio) even the ones of the same type from the same manufacture might not cross. So you can't always take on out of on make Pontiac and put it in another make Pontiac of the same year.


11

Yes, it is useful, okay and won't cause any damage. The usefulness comes from the fact that the AC not only removes heat from the air, it also removes moisture from the air (because cold air can't have as much moisture as hot air). The removed moisture clears your windows quickly. The only "damage" caused is the additional fuel consumption. On most new ...


10

There is no real point in doing a resistance measurement. BWM, like with most other stuff, decided to put more in there than you need. They have put active elements in there, that control the current through the motor based on a control input signal, this is nothing to do with a bad resistor, but with some failure in the transistor-drive somewhere inside ...


9

The short answer to your question is no. As @JPhi1618 noted, the compressor is mechanically driven. Without the compressor you don't have any cooling. The AC runs by changing the state and pressure of a liquid, and compressing the liquid is a big part of that cycle. If you bolted an electric compressor onto the car you would have to find a way to switch ...


8

Yes, this is possible. Several companies (VAG, BMW) have switched to AC units that are driven by electric motors. For BMW, this is part of their Efficient Dynamics strategy, where they'll switch the compressor on/off depending on engine load to optimize fuel consumption. When the weather's not too hot, you can run the compressor intermittently without the ...


8

I think the visor is right… When you put the visors down (or at the "right" angle) they stop the airflow from the defroster vents from being able to move across the headliner. They may even deflect the heated air down in a way that causes a "rotor" of warm air in the vicinity of the windshield. This both helps to warm the windshield and gives more time for ...


6

It will depend on your car, the outdoors humidity, the air temperature and the engine temperature. As an example, for me on a cold icy morning starting with a cold engine: aircon on fan on low use external air, not recirculator! front windscreen demister (covers wiper rest area) rev engine until at working temp then put fan on high But in high humidity ...


6

The reason for the odor is that water condenses inside the ducts when the AC cools the air. Though there are drains, there will still be enough moisture in the system to allow mold to grow. The heating is usually placed after the AC. This is useful for screen defogging: The air is first dehumidified by the AC and then heated, which gives warm, extremely dry ...


6

For an A/C system to be functioning correctly, you need: In the cabin: something to exchange cold (an evaporator) something to move air over the evaporator (the fan) a working blend door that allows the user to select heat or cold In the engine compartment: something to exchange heat (a radiator) something to move air over the radiator (radiator fan) a ...


6

You need to prevent the buildup of mildew in the system during the colder months, as that's what causes the smell. One trick I've heard is to make sure you run the A/C regularly (at least once every couple of weeks) during the cooler period, so that any spores get blown out of the ducts before they get a chance to settle and grow - a useful side effect is ...


6

No. Sorry. Absolutely not. If you stay within the same marque/brand you might have half a shot. For instance, a Chevy Cruze HVAC module has a better chance of working in your Pontiac, as GM, Ford, and many others like to share basic part properties across entire lines and platforms. Simple matter of saving money and cost of manufacture. Your Subie HVAC ...


5

Possible Causes: Coolant Level Thermostat stuck open Heater Control Valve Temperature blend door Plugged heater core Coolant Level Coolant level that's even a little low can affect heater performance. It's near the top of the system so there could be enough coolant to prevent the engine from overheating but not enough to make it through the heater core. ...


5

Here's an image to a cooling system for your reference. Each vehicle has it's own unique setup. The differences in some cases are slight and in some very big. You can see the placement of your heater core. Here's another image of a general layout for an AC system. A Haynes service manual is about $20. They are worth their weight in gold if that's ...


5

One way I could explain it from that photo, is that there will not have been any snow under the car, so the exhaust fumes will have easily been able to exit from the tail pipe and spread under the car. The fumes will then have gone into the engine compartment and from there could have been sucked in by the fan. Alternatively the exhaust could have had a ...


5

I would assume the visors would help to create / trap a column of slightly warmer air at the top the of screen instead of is dissipating across the headliner and into the cabin of the car.


5

In a nutshell: The radiator fan comes on so the A/C works at its highest efficiency. The A/C condenser (the part which sits in front of the coolant radiator) is a heat exchanger. If air isn't flowing over it, it won't exchange the heat it needs get rid of so the A/C core inside the vehicle can become cold and make you comfortable. If the fan didn't come on,...


5

I live in a very hot climate. There is no issue in turning on a properly-functioning A/C to its maximum setting at startup. Turning the A/C on activates the refrigeration cycle, which at startup will have the same load on the compressor regardless of the temperature setting selected. This is part of the reason why the cooling effect isn't instantaneous, ...


4

Great post, it really helped me solve the same problem. I took some photos specific to the Nissan Note, I can send them if you want to expand the article. My problem turned out to be a failed solder joint on the resistor board. Firstly remove the glove box by taking out 5 screws (2 underneath and 3 on top) BLUE circles... remove the glove box and look for ...


4

Hot air from the exterior with your a/c on is the quickest. Though in general having the a/c on is the most important piece, as it removes moisture from the air.


4

Bad AC odors are usually related to poor drainage of condensation, which allows mold to grow. There is a small drain hose which allows the condensation to drip out, but this can get clogged up or blocked by dirt. If this is the cause, then simply cleaning out the drain may be enough to clear things up. A quick google for your car model and air ...


4

bad air duct door You have multiple air duct doors in your car. One of them will control the air from your heater. You may have situation where the servo motor is bad in a particular door. Sometimes you can have a situation where hot air comes out of one vent and cold air comes from another and various combinations of the issue that maps back to a bad ...


4

One trick that has worked well for me in preventing the musty smell is to turn the A/C off but leave the blower on about a minute or so before reaching your destination (if you are going to be parked for a while). It seems this allows accumulated moisture in the system to be removed before shutting the blower down.


4

The air con water outlet pipe might be clogged. Get it cleaned by a mechanic. Happened to me some time ago, cleaned the outlet and now everything is fine.


4

Check the blower motor resistor. When it goes bad it defaults to high speed. The resistor is usually near the blower motor.


4

The condenser is placed earlier in the flow of air coming from outside as it needs to cool the gas rapidly and the radiator is not affected too much by slightly warmer air. The A/C condenser only warms the outside air up a small amount as the gas being cooled (refrigerant) only needs a small amount of heat removed to change it to a liquid - while the water ...


4

No, the outside temperature sensor should not affect the HVAC. That sensor is only there to give you the outside temperature reading on your dash. Modern climate control systems use temperature sensor(s) inside the car to control the temperature. It wouldn't make sense for the system to be metering from outside temperature if it's below freezing outside, but ...


3

Your Sonata has a cabin air filter (CAF). You should try to change that out first. More than likely, you have some mildew built up somewhere. The CAF is the first place to start.


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