ttran984

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?

gamma300C

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

ttran984

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”.

halex

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?

GMoney!!!

mu car is doing exactly this. Did you figure out a solution?