It's amazing just how much engineering goes into literally everything and we never know anything about it, things 'just work'. Lots of smart people did a lot of thinking to make our lives so comfortable.
There's no one in the world that can explain that so good and easy to understand. A little fast but no bullshitting. Straight to the point and explain in quite a bit of detail. Seriously he just taught a whole semester of classes in a few minutes
Engineering is an art… very few people are aware of these mechanisms that are in the background the work with the push of a button.. Very informative video ❤✨
That's very impressive! Someone, or a team had to design all those ducts and mechanisms to fit in a rather small space and not rattle around when driving!
After seeing this I fully understand how the AC system actually works! The freon that heats up as it cools down air turns into gas and has to be turned back into a condensed liquid (cooler) and compressed to be used again. Really smart design!
Amazing videos. Thank you for doing this. Even though I knew the principle of how it works I never saw it disassembled. I hits me how cheap and prone to failure the components are. Crappy little hobby motors, plastic gears without a lick of grease - it's terrifying. Thank you for showing us this!
You are welcome! It sure is interesting to understand the engineering that goes into making a car work on things like this that you often don't see or think of!
So since running the fan at a lower speed just means that there is extra electrical resistance added to the circuit, does it take just as much electricity to run the fan at full speed as it does to run it at low speed?
No, it takes less electrical energy at the lower setting. As the total resistance of the circuit is higher, the current will be lower, therefore the total consumed power will be lower.
@@fritsified5952 The total resistance is higher due to the heating elements used as resistors. So, like and electric stove the energy is being used.Note that the elements are monted in the air duct to dissipate the heat.
The answer to this question has potentially upsetting implications for how I've lived my life. I regularly use lower fan speeds in my car and home so I don't use as much electricity. Have I suffered through hot nights when turning my bedroom fan higher would use no more electricity?
That is what VW calls a semiautomatic single zone HVAC system, in marketing terms is called Climatic. There is an even fancier system in which everything is automatic (air distrutibution) and has dual zone climate control with more temp sensors, electic acutators and fan speeds. It's esentially the same system, but with additional components which is called Climatronic. On both systems, the interior temp sensor is an infrared sensor located in the middle of the climate control panel. In this video, you can see it between defrost, recirculation and ECON buttons.
Wow good to know. You can definitely tell where the climatronic would have been in the mould for the dual zone by having the passenger and driver flaps separate
Excellent explanation as always like your other vids. Just replaced the resistor on my NZ based Tiida/Versa. I discovered that on an online manual, you can run simple manual diagnostics to display codes for the actuators and circuits and display temperatures for the heaters' input sensors. Probably heater diagnostics can be done for the Jetta.
Thank you speedkar99 your whole videos what I am watching since last 3 years are really educational. through those videos I could understand automotive engineering based on textbook knowledge Man you have nice day and Keep health, thank you again
Such a complex system where many things can go wrong. My car has a slider for the temperature control and a slider for the fan speed. But buttons for the vent control. I never realized that everytime i press those buttons some servos or something moves those vents. The temperature slider is not hard to push, so I suspect that the temperature control is also electric.
The T-7 ASE I failed today by 2 questions. Now I have to wait 30 days to retest. Good thing the A-7 is still a/c heater related so I’ll do “auto” first then retake the “truck” version after my 30 day cooldown period of failure
I always wonder why, because it sucks in all the debris from the trees I use to park under. The blower comes before the filter, so maybe you get a rattle from a leaf. I have to throw out the filter every year. The motor filter is engineered better.
2:07 Since 12V are being used regardless of blower speed, does setting the AC to 1 use just as much gas as 4 if the compressor is running off the engine?
The heater core is always recilculating coolant even when it's summer and HVAC system is off building up heat slowly at your cabin (some cars have electric heater core valve chocking the coolant flow)
Some companies designed to fix that, and the heater core is right in front of a firewall (aka super good insulation) that keeps heat from going behind the engine bay.
It amazes me how well he can explain the sequence of operations but has no idea that the condenser and evaporator are called COILS not cores. Gotta love engineers. Geniuses with no practical understanding
When we set the dial to the lowest blue or the digital temperature to the lowest setting, are we closing the path to the heater core or requesting the thermostat (temperature sensor) to read lower temperatures?
Hello, got any idea what might cause a burnt smell with the heating on, and also some additional noise even with the fan on the lowest setting? Audi A4 B9 TDI.
@@speedkar99 yea but most the time the linkage breaks or comes off or gets out of alignment. Still anything better then having all the blend doors controlled by electric motors cause when they fail you gotta pull the whole dash out.
When the evaporator core is being blown by the fan I hear it builds up moisture and there is some kind of drain pan for all of it, is this part of the HVAC system behind the dash?
My doubt is. In heating mode, where does the air blown in the evaporator come from? Is it taken directly from the outside? Will that blow air have the same temperature as the air outside of the car before passing through the evaporator?
can you explain the difference in Honda accord, @ 3.11 sec, cross sectional view, In Honda accord, First filter comes, then blower motor and then evaporator, why this is different?
Very informative. Thanks. I was actually looking. for a video on how the system differs between one for ICE cars and Battery Electric Vehicle (EV) where there are no hot liquid from the engine to regulate the air temperature out of the vents. Does EV use compressor rotation speed controllers to regulate air temperature instead?
My question might not be related to this video, What is the torque of the cordless impact wrench that you use in engine teardown videos? I expect you to answer me, thanks a lot
I came across your channel and now I’m subscribed. Your vids are really cool and very informative. One question….are you selling your own brand of toothbrushes?
@@speedkar99 i see.but one more question,the thermistor is attach on evap fin,how could it know when cabin tempreture is reach desire settting?all car is the same principle?
May i ask a question, sorry for my ignorance but if the temperature switch only open de heat air, then is false that thing about the air in 24c sabes fuel and shit right? Like the compresor never stop working so is better just leave it at max cool
@@speedkar99 thanks for the answer, i see so many people saying “oh no you need to put 24celsius because of the fuel consumption. So when does the ac compressor stop working? If it doesn’t work like the ac of the wall, sorry for my english i’m a native spanish person
Can we use PWM motor controller as the fan speed controller to have a wide range speed selection from 0 to 100%? I also planning to make a custom hvac controller using Arduino, OLED screen and rotary encoder for my 1988 Cressida because the OEM control unit and wiring has been hardwired by the previous owner. Can I replace the flap actuators with something like SG90 PWM servo so I can control the airflow using some microcontroller?
Your spiral gear is my "worm" gear. Just hope the plastic bit n pieces don't become brittle and crack and snap. I had two German cars and both had heater core issues buried deep in the dash, to be fair they weren't young cars but even so.
Another question How to know exactly the speed of air for each level (I’m simulating air flow on a software….) I didnt find anything regarding this in the manual
If I understand this correctly, if the temperature gauge is set to lowest, then the cold air goes straight to the vents. If the temperature gauge is set a little higher, maybe 75 degrees, then the cold air gets mixed with hot air and blown to the vents
True, I tested on my Nissan Tiida with Auto mode. The lowest temp setting of 18 Celsius defaults to the upper vents. Higher Temps defaults to the lower foot vents. Also found if higher Temps are manually set fully to lower foot vents, a little heat exits the upper far left and right vents but not the middle upper two vents.
My brand new accord 2.OT makes a weird sound only when I turn the heat on when it’s cold outside.. it only does that when the weather drops. It’s driving me crazy. Anybody out there knows what might be the problem. Please!
Possible a dumb question: I don’t remember seeing anything like that when I’m under the hood, is that stored under the dashboard? Like in between the engine bay and the infotainment system? Edit: you mentioned the blower motor is under the dash, so that probably answered my question 😅
My ac compressor clutch wasn't engaging. I come to find out the PCM relay was physically damaged with a hole in it. I've been getting bad gas mileage I went ahead and replaced it. Now my Ac compressor engages it starts for 5 seconds and then stops and it keeps doing that every like few minutes. With ac turned max all I get is hot air. Do you think it's the relay? Low refrigerant? Bad ac compressor? Thanks in advance i liked the video and subbed!
It's amazing just how much engineering goes into literally everything and we never know anything about it, things 'just work'. Lots of smart people did a lot of thinking to make our lives so comfortable.
Agreed. We take this for granted yet use it everyday
There's no one in the world that can explain that so good and easy to understand. A little fast but no bullshitting. Straight to the point and explain in quite a bit of detail. Seriously he just taught a whole semester of classes in a few minutes
I'm glad you appreciate my video style, thanks
Engineering is an art… very few people are aware of these mechanisms that are in the background the work with the push of a button.. Very informative video ❤✨
That's very impressive! Someone, or a team had to design all those ducts and mechanisms to fit in a rather small space and not rattle around when driving!
To be fair, the design is very similar to the mk5 Jetta. So the design itself is at least from 2007. And was still being used up until the mk7 Jetta.
This is from a mk5 2006 Jetta tdi
Agreed!
Some guys explain the practical and others the theory part.But you explained both with diagrams.Well done bro.❤
After seeing this I fully understand how the AC system actually works!
The freon that heats up as it cools down air turns into gas and has to be turned back into a condensed liquid (cooler) and compressed to be used again. Really smart design!
It sure is an innovative design. If only they could make it more efficient
Great job, respect to the people that designed this, you’d think they’d go wrong all the time with the amount of stuff packed in there.
Agreed! It's something we don't see or think of and it just works
Agreed! It's something we don't see or think of and it just works
Mind blown to the level of engineering involved in here!
You've really mastered your craft. A pleasure to watch and be educated
You are the only one explained so so so clear and very detailed. I really appreciate of your video.
Very good and speedy explanation (as opposed to slow and boring) of the entire AC process and related equipment. Thank you so much! 5 Star review!!
Thanks..short and to the point is my style
You are legend 👍
I haven’t seen more complicated hvac on any car period
Hummm, this is a pretty basic setup, i don't see anything that could be removed without loosing core functionalities
No one can explain in a better way as you did. Simply Amazing!!!..Thanks a lot for the video.
Glad you liked it!
Bro you are amazing. Everything is well explained with one toothbrush.
this is very well done. I love the schematics to help visualize everything
What an awesome video. I have a Mk5 Golf which has this unit so I’m amazed at what is under my dashboard.
Glad you enjoyed it. The HVAC system is quite a marvel that no one ever thinks about.
Really appreciate this video as I'm trying to figure out why the AC isn't as cold as it should be in my Honda Fit!
I would so much rather pull a transmission or an engine than pull a heater core...ugh....you got dedication bro!
Amazing videos. Thank you for doing this. Even though I knew the principle of how it works I never saw it disassembled. I hits me how cheap and prone to failure the components are. Crappy little hobby motors, plastic gears without a lick of grease - it's terrifying.
Thank you for showing us this!
You are welcome! It sure is interesting to understand the engineering that goes into making a car work on things like this that you often don't see or think of!
So well explained on such a complex , clever engineered system..
It sure is some interesting engineering behind something we take for granted
So since running the fan at a lower speed just means that there is extra electrical resistance added to the circuit, does it take just as much electricity to run the fan at full speed as it does to run it at low speed?
Yup. That's correct.
Newer cars use either pulse with modulated DC motors or brushless DC motors.
Never thought of that
No, it takes less electrical energy at the lower setting. As the total resistance of the circuit is higher, the current will be lower, therefore the total consumed power will be lower.
@@fritsified5952 The total resistance is higher due to the heating elements used as resistors. So, like and electric stove the energy is being used.Note that the elements are monted in the air duct to dissipate the heat.
The answer to this question has potentially upsetting implications for how I've lived my life. I regularly use lower fan speeds in my car and home so I don't use as much electricity. Have I suffered through hot nights when turning my bedroom fan higher would use no more electricity?
There is simply NO other channel like this
Well I'm glad I'm here then 🙂
Watching from Al Khafji Saudi Arabia thank you for very informative Vlog
You are welcome from Canada
Your breakdown videos are hands down the best on UA-cam.
Great video , you should make more of them in in this style !
I have a lot of teardown videos like this. Suggestions are welcome
That is what VW calls a semiautomatic single zone HVAC system, in marketing terms is called Climatic. There is an even fancier system in which everything is automatic (air distrutibution) and has dual zone climate control with more temp sensors, electic acutators and fan speeds. It's esentially the same system, but with additional components which is called Climatronic.
On both systems, the interior temp sensor is an infrared sensor located in the middle of the climate control panel. In this video, you can see it between defrost, recirculation and ECON buttons.
Wow good to know. You can definitely tell where the climatronic would have been in the mould for the dual zone by having the passenger and driver flaps separate
Excellent excellent excellent job
Imagine the manpower that went behind building that bad boy! 😮 just incredible
Very impressive as always!!!
Thanks
Excellent explanation as always like your other vids. Just replaced the resistor on my NZ based Tiida/Versa. I discovered that on an online manual, you can run simple manual diagnostics to display codes for the actuators and circuits and display temperatures for the heaters' input sensors. Probably heater diagnostics can be done for the Jetta.
Super helpful ! Extraordinary detail !!
Thanks !!! 👊🏼
Glad you liked it!!
I wanted to understand this mechanism of cabin air, really thanks to you brother. Love ❤️
Thanks for the master class!
Never knew they included an electric resistance heater in the HVAC system. Crazy!
Thank you speedkar99 your whole videos what I am watching since last 3 years are really educational. through those videos I could understand automotive engineering based on textbook knowledge Man you have nice day and Keep health, thank you again
Glad you like it and all the best on your automotive stuides
My mom has a car that has a heater that would only work on certain settings and I may have figured out why! Thanks!
The most brilliant explaininq I have ever seen and heard
Sure is interesting, especially the way each brand handles these same tasks.
This explains everything, thank you 👍👍
Amazingly explained 🔥
Thank you for the information.
Thanks for your cool demonstration 👍
You are welcome
My old 70s chevy still has 5 crank air conditioning. Much less complicated. Great videos!!!
Thanks
Amazing work
Thanks. This was quite an involved
@@speedkar99 😀😂yes
so informative omg thank you so much
You're so welcome!
Such a complex system where many things can go wrong. My car has a slider for the temperature control and a slider for the fan speed. But buttons for the vent control. I never realized that everytime i press those buttons some servos or something moves those vents. The temperature slider is not hard to push, so I suspect that the temperature control is also electric.
The T-7 ASE I failed today by 2 questions. Now I have to wait 30 days to retest. Good thing the A-7 is still a/c heater related so I’ll do “auto” first then retake the “truck” version after my 30 day cooldown period of failure
Always wondered where the "outside air" came from. 👍
Under the wiper cowl
I always wonder why, because it sucks in all the debris from the trees I use to park under. The blower comes before the filter, so maybe you get a rattle from a leaf. I have to throw out the filter every year. The motor filter is engineered better.
0:50 Yes, After all These Years! Finally A Vent in Glovebox To Keep My Gloves Nice And Cool For those Hot Summer Months!.
Thanks for the teardown
You are welcome
2:07 Since 12V are being used regardless of blower speed, does setting the AC to 1 use just as much gas as 4 if the compressor is running off the engine?
The heater core is always recilculating coolant even when it's summer and HVAC system is off building up heat slowly at your cabin (some cars have electric heater core valve chocking the coolant flow)
Some companies designed to fix that, and the heater core is right in front of a firewall (aka super good insulation) that keeps heat from going behind the engine bay.
this system is so complicated thanks
Wait until you see the automatic dual zone HVAC systems
brilliant explanation. Thank you
It amazes me how well he can explain the sequence of operations but has no idea that the condenser and evaporator are called COILS not cores. Gotta love engineers. Geniuses with no practical understanding
Great video, thanks so much. You helped me a lot
Amazing and wonderful video , thanks
When we set the dial to the lowest blue or the digital temperature to the lowest setting, are we closing the path to the heater core or requesting the thermostat (temperature sensor) to read lower temperatures?
Hello, got any idea what might cause a burnt smell with the heating on, and also some additional noise even with the fan on the lowest setting? Audi A4 B9 TDI.
Sounds like you've got something stuck in the HVAc blower melting up
@@speedkar99 Thanks, guess I'll have to remove the blower...
r u psychic? this is exactly what i needed, my ac was making a noise yesterday. i think i can figure it out now.
Glad it helped
Another cool video. Just like this one.
great teacher indeed, Regards
Alot more to this hvac system then my 2001 jeep grand cherokee hvac system. Same in a way but different
The best HVAC systems in cars are the ones we’re all the blend doors are controlled by engine vacuum. Those never fail.
What about mechanical linkages?
@@speedkar99 yea but most the time the linkage breaks or comes off or gets out of alignment. Still anything better then having all the blend doors controlled by electric motors cause when they fail you gotta pull the whole dash out.
Great explanations as always :)
Awesome video
Thanks!
Great video and thank you.
Awesome video 👌
Thanks
Some heater cores from the cabin are gonna be a
pain to replace
All heater cores are a pain, but apparently on this Jetta it can be done without dash removal from the driver footwell
When the evaporator core is being blown by the fan I hear it builds up moisture and there is some kind of drain pan for all of it, is this part of the HVAC system behind the dash?
My doubt is. In heating mode, where does the air blown in the evaporator come from? Is it taken directly from the outside? Will that blow air have the same temperature as the air outside of the car before passing through the evaporator?
can you explain the difference in Honda accord, @ 3.11 sec, cross sectional view, In Honda accord, First filter comes, then blower motor and then evaporator, why this is different?
Very informative. Thanks. I was actually looking. for a video on how the system differs between one for ICE cars and Battery Electric Vehicle (EV) where there are no hot liquid from the engine to regulate the air temperature out of the vents. Does EV use compressor rotation speed controllers to regulate air temperature instead?
Yes, check out my hybrid compressor video, it's all electric
If I want to clean evaporator - can I use foam cleaner and spray it into car air vent? Can I reach evaporator through center air vent?
My question might not be related to this video, What is the torque of the cordless impact wrench that you use in engine teardown videos? I expect you to answer me, thanks a lot
It's an M18 1/2" miluakee impact wrench
Great information
Could you please show us how to replace blower motor fan ?
I twisted it and pulled it out in the video. In the vehicle, you'd do the same under the passenger footwell
I came across your channel and now I’m subscribed. Your vids are really cool and very informative. One question….are you selling your own brand of toothbrushes?
No, I don't have my own brand yet
Ok….LOL….I have a similar toothbrush I am now using for utility work as well!
as video show max cool on thermostat resistor 18c,but why when i measure air from aircond vent max can reach 4c before compressor cut off.
18C is the cabin temp not the air vent temp
@@speedkar99 i see.but one more question,the thermistor is attach on evap fin,how could it know when cabin tempreture is reach desire settting?all car is the same principle?
Is it advisable or OK to set your AC temp to the lowest setting? Will there be changes to engine load or FC?
May i ask a question, sorry for my ignorance but if the temperature switch only open de heat air, then is false that thing about the air in 24c sabes fuel and shit right? Like the compresor never stop working so is better just leave it at max cool
Yes
Only when the compressor is off you save fuel regardless of the mixer position.
@@speedkar99 thanks for the answer, i see so many people saying “oh no you need to put 24celsius because of the fuel consumption.
So when does the ac compressor stop working? If it doesn’t work like the ac of the wall, sorry for my english i’m a native spanish person
Can we use PWM motor controller as the fan speed controller to have a wide range speed selection from 0 to 100%?
I also planning to make a custom hvac controller using Arduino, OLED screen and rotary encoder for my 1988 Cressida because the OEM control unit and wiring has been hardwired by the previous owner.
Can I replace the flap actuators with something like SG90 PWM servo so I can control the airflow using some microcontroller?
Yes. That's basically how it's controlled with automatic HVAC systems. See my other video on that
So the air filter is after the fan? So it's not protected from dust and debri?
love your videos
Me too
I have a 2020 Forte Kia when I turn on the heat the AC also automatically runs which I have to turn off the ac is that normal ?
Are all AC found in hybrid car powered by the battery and not the engine connect by belt?
If the fan doesn't coold the condensor can the system be warm
It's the gas inside that makes it cool
Not the temperature of the fluid or pipes or condensor outside.
Your spiral gear is my "worm" gear. Just hope the plastic bit n pieces don't become brittle and crack and snap. I had two German cars and both had heater core issues
buried deep in the dash, to be fair they weren't young cars but even so.
How did you research how it all works?
What if your car is cool on ine side and hit on the other when yiu turn in the AC
Does a small bug could make any error to the system
It could
Brother when are you doing the TDI tear down?
Eventually when I get to it.... working on. Subaru WRX engine right now
Quick question
Can having a bad wheel bearing cause brake pads to wear faster?
Yes, unevenly because the hub is no longer true and wobbles
Very nice video
But I have a question ,I didn’t understand the air flow path when recir- mode on?Thanks btw
Another question
How to know exactly the speed of air for each level (I’m simulating air flow on a software….)
I didnt find anything regarding this in the manual
If I understand this correctly, if the temperature gauge is set to lowest, then the cold air goes straight to the vents. If the temperature gauge is set a little higher, maybe 75 degrees, then the cold air gets mixed with hot air and blown to the vents
True, I tested on my Nissan Tiida with Auto mode. The lowest temp setting of 18 Celsius defaults to the upper vents. Higher Temps defaults to the lower foot vents. Also found if higher Temps are manually set fully to lower foot vents, a little heat exits the upper far left and right vents but not the middle upper two vents.
My brand new accord 2.OT makes a weird sound only when I turn the heat on when it’s cold outside.. it only does that when the weather drops. It’s driving me crazy. Anybody out there knows what might be the problem. Please!
Possible a dumb question:
I don’t remember seeing anything like that when I’m under the hood, is that stored under the dashboard? Like in between the engine bay and the infotainment system?
Edit: you mentioned the blower motor is under the dash, so that probably answered my question 😅
My ac compressor clutch wasn't engaging. I come to find out the PCM relay was physically damaged with a hole in it. I've been getting bad gas mileage I went ahead and replaced it. Now my Ac compressor engages it starts for 5 seconds and then stops and it keeps doing that every like few minutes. With ac turned max all I get is hot air. Do you think it's the relay? Low refrigerant? Bad ac compressor? Thanks in advance i liked the video and subbed!
Check the refrigerant
If my system it cooling and high speed it gets hot ???
Does it get cool when you idle?
Thanks...😍😍
Welcome
Thanks a lot
When I set temperature at 18.0, i get cool air but i set at 18.5, i get very hot air. Why's that?
Hmm