W204 No air coming out of vents
Thread Starter
Newbie
Joined: Feb 2018
Posts: 8
Likes: 1
2012 Mercedes C300
W204 No air coming out of vents
I just had my alternator and battery replaced on my W204 recently due to a failed voltage regulator but besides that nothing else recently. Now, when I start my car it will randomly, even on max speed, no air will come out of the vents (hot or cold). Then I will restart my car and then randomly it will work again. Since it is cold it will come out hot which I have it set on highest temp due to the cold where I live.
Anyone had the same issue or fix for this problem?
Anyone had the same issue or fix for this problem?
Super Member
Joined: Jun 2017
Posts: 608
Likes: 107
From: Western NC
2009 MB C300 Sport 4matic
It isn't your HVAC motor control module if ,as you say, you can get the fan to work...does it run on all the different speeds ? With the key on , pushing the climate control buttons for upper vents, lower vents, etc, you should hear the flaps opening or closing (when you hit the OFF button). Obviously, this should occur when the system seems to be working and not when you get "no air from vents". The voltage regulator problem may have damaged the control unit which is fairly cheap to replace as a used unit. See link.
I would check all the control panel's functions..A/C, defrost mode, vent selection modes, temp settings when intermittent failure has occurred to confirm which settings don't work. A used unit replacement might be a cheaper first try at a fix before getting the MB Dealer involved. YouTube has DIY videos on how to remove/install climate control unit...pretty straight forward. An oddball idea would be to check the air intake on the firewall behind( remove)
the battery cover just to make sure nothing got stuffed in there by mistake..not likely but strangers things have happened !
https://oemusedautoparts1.com/produc...RoCSrsQAvD_BwE
I would check all the control panel's functions..A/C, defrost mode, vent selection modes, temp settings when intermittent failure has occurred to confirm which settings don't work. A used unit replacement might be a cheaper first try at a fix before getting the MB Dealer involved. YouTube has DIY videos on how to remove/install climate control unit...pretty straight forward. An oddball idea would be to check the air intake on the firewall behind( remove)
the battery cover just to make sure nothing got stuffed in there by mistake..not likely but strangers things have happened !
https://oemusedautoparts1.com/produc...RoCSrsQAvD_BwE
Thread Starter
Newbie
Joined: Feb 2018
Posts: 8
Likes: 1
2012 Mercedes C300
It isn't your HVAC motor control module if ,as you say, you can get the fan to work...does it run on all the different speeds ? With the key on , pushing the climate control buttons for upper vents, lower vents, etc, you should hear the flaps opening or closing (when you hit the OFF button). Obviously, this should occur when the system seems to be working and not when you get "no air from vents". The voltage regulator problem may have damaged the control unit which is fairly cheap to replace as a used unit. See link.
I would check all the control panel's functions..A/C, defrost mode, vent selection modes, temp settings when intermittent failure has occurred to confirm which settings don't work. A used unit replacement might be a cheaper first try at a fix before getting the MB Dealer involved. YouTube has DIY videos on how to remove/install climate control unit...pretty straight forward. An oddball idea would be to check the air intake on the firewall behind( remove)
the battery cover just to make sure nothing got stuffed in there by mistake..not likely but strangers things have happened !
https://oemusedautoparts1.com/produc...RoCSrsQAvD_BwE
I would check all the control panel's functions..A/C, defrost mode, vent selection modes, temp settings when intermittent failure has occurred to confirm which settings don't work. A used unit replacement might be a cheaper first try at a fix before getting the MB Dealer involved. YouTube has DIY videos on how to remove/install climate control unit...pretty straight forward. An oddball idea would be to check the air intake on the firewall behind( remove)
the battery cover just to make sure nothing got stuffed in there by mistake..not likely but strangers things have happened !
https://oemusedautoparts1.com/produc...RoCSrsQAvD_BwE
Thank you for the information, I just figured out when I turn the car on and the issue is occurring. I turn off the climate control and wait a moment then turn it back on it works again. From what I’ve used so far every function works except for when it has the issue of nothing coming out of the vents until I basically “turn it off and on”.
Junior Member
Joined: Oct 2018
Posts: 18
Likes: 8
C-class 200CDI
Similar problem here
Air blower motor is working fine - it reacts on increase/decrease fan speed and you can hear it clearly when you do this.
Cooling from the air conditioner is also working nice (when it is working) and cold air is blowing from the air vents and reacts on the controls.
Sometimes, while driving, it just stops blowing the air through the vents and you can feel just super gentle breeze from the air vents, no matter if you start increasing the fan speed, or put it to maximum, or to auto, or play with climate control to put all the air into the middle section.
Then, I stop at gas station to refuel the car and after these 10 minutes when I start the car again it starts to work normally again. Sometimes it didn't start to work normally for for few days and then just decide to start working when it thinks it should.
Hate this problem and would like to fix it. Did replacement of climate control unit helped you?
Cooling from the air conditioner is also working nice (when it is working) and cold air is blowing from the air vents and reacts on the controls.
Sometimes, while driving, it just stops blowing the air through the vents and you can feel just super gentle breeze from the air vents, no matter if you start increasing the fan speed, or put it to maximum, or to auto, or play with climate control to put all the air into the middle section.
Then, I stop at gas station to refuel the car and after these 10 minutes when I start the car again it starts to work normally again. Sometimes it didn't start to work normally for for few days and then just decide to start working when it thinks it should.
Hate this problem and would like to fix it. Did replacement of climate control unit helped you?
Newbie
Joined: Jul 2024
Posts: 1
Likes: 0
W204
Any resolution?
Air blower motor is working fine - it reacts on increase/decrease fan speed and you can hear it clearly when you do this.
Cooling from the air conditioner is also working nice (when it is working) and cold air is blowing from the air vents and reacts on the controls.
Sometimes, while driving, it just stops blowing the air through the vents and you can feel just super gentle breeze from the air vents, no matter if you start increasing the fan speed, or put it to maximum, or to auto, or play with climate control to put all the air into the middle section.
Then, I stop at gas station to refuel the car and after these 10 minutes when I start the car again it starts to work normally again. Sometimes it didn't start to work normally for for few days and then just decide to start working when it thinks it should.
Hate this problem and would like to fix it. Did replacement of climate control unit helped you?
Cooling from the air conditioner is also working nice (when it is working) and cold air is blowing from the air vents and reacts on the controls.
Sometimes, while driving, it just stops blowing the air through the vents and you can feel just super gentle breeze from the air vents, no matter if you start increasing the fan speed, or put it to maximum, or to auto, or play with climate control to put all the air into the middle section.
Then, I stop at gas station to refuel the car and after these 10 minutes when I start the car again it starts to work normally again. Sometimes it didn't start to work normally for for few days and then just decide to start working when it thinks it should.
Hate this problem and would like to fix it. Did replacement of climate control unit helped you?
Junior Member
Joined: Oct 2018
Posts: 18
Likes: 8
C-class 200CDI
Answer
I bought first new climatronic central panel module. Found one that was sitting for 10 years in a stock and bought it for around 150€ (instead of 850€ from the dealer), replaced the old one and program it but it didn't help - the symptom occurred again in one longer trip previous summer. Then I decided to replace blower motor together with blower motor regulator and found these new two OEM parts for a very good money (was lucky) and paid really good price instead of 1000€ for both. I had some non-OEM parts before (Hella blower and Mahle regulator) and now I have OEM parts. Will see if error occurs. Yesterday I made 350km and air-condition was working without any problem, I think the OEM parts also works better - it looks to me that it is cooler inside the cabin. With non-OEM parts it was hardly enough coolness in the cabin - minimal acceptance level.
Last edited by halex; Jul 18, 2024 at 05:47 AM. Reason: mistakes
