Changing the blend door actuator

Tiny
VIVEKHB
  • MEMBER
  • 2003 MERCEDES BENZ C230
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 230,000 MILES
I don't have hot air coming from all the vents on the driver side, i.E. The windscreen, small vent on the dash near the drivers door and the front vent.
I think it is the M2/6-Lt blend air flap position motor that has failed, but I am not sure about it. This motor is under the car frame to which the steering column is attached.
I don't know how to free the steering column as I have never done this before.
Sir, your help will be highly appreciated.
My VIN:WDBRN 40J 53A 472958.
Thursday, April 2nd, 2020 AT 8:31 AM

23 Replies

Tiny
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I would agree that this appears to be the issue. However, the procedure is attached and it doesn't have you remove the column. There should be access once you remove the cover under the column.

Let me know if you have questions and we can go from there. Thanks
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Thursday, April 2nd, 2020 AT 9:23 AM
Tiny
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Sir, thanks for your reply.I want to make sure are all the actuators interchangeable, and secondly which motor is responsible for the drivers side air flow.I have added a photo.
This is the exact illustration of my car. Waiting for your answer.
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Thursday, April 2nd, 2020 AT 6:47 PM
Tiny
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The Left blend air door is what controls the temp of the air for the driverside. The fan speed is what controls the amount of air coming through the system.

From what I can tell the actuators are interchangeable even though the part numbers are different. The aftermarket parts websites only list one part for these actuators which supports the idea that they are.
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Friday, April 3rd, 2020 AT 9:17 AM
Tiny
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Sir, thanks for your advice. So I have to change the M2/6 motor for the drivers side lacks hot air. But the motor is situated under the frame. Unless I remove the frame I don't have access to the motor, and the intermediate steering shaft is attached to the frame.
So please advice me as to dismantle the steering column from the frame. There are no such videos on YouTube. Waiting for your reply.
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Friday, April 3rd, 2020 AT 10:15 AM
Tiny
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Sorry for the delay. I have been looking numerous times for this information. Not only did they not publish a procedure for what you are looking for but they say that the frame and column do not need to come out to do the actuator.

I attached the process closest to what I can tell you are asking for. I am thinking that I am not understanding the component you are trying to change. Is it the actuator for the driverside door? If so, the first attachment is the process for that actuator.
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Saturday, April 4th, 2020 AT 8:47 AM
Tiny
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Sir, thanks a lot for your information. As you rightly said, it is the actuator for the driver side door. Please can you send me the diagram of the removal of the steering coupling(25), so as to get an idea as to remove the frame. Sorry to bother you. Have a blessed weekend, bye.
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Saturday, April 4th, 2020 AT 2:17 PM
Tiny
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Okay. Here is the process for the steering coupling. Hopefully this gets you to where you need to be. Let me know if there is another component and I will see if they have that as well.

You have a blessed weekend as well.
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Saturday, April 4th, 2020 AT 4:18 PM
Tiny
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Thanks a lot Sir. As soon as I receive the actuator I will start the job.I will be in touch with you as I progress with the job. Thank you once again. Have a blessed weekend, bye.
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Saturday, April 4th, 2020 AT 4:32 PM
Tiny
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Sounds great. Thanks for the update. Please let us know how you make out. Thanks
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Saturday, April 4th, 2020 AT 5:09 PM
Tiny
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Sure, I will. Thanks a lot once again. Have a blessed day, bye.
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Sunday, April 5th, 2020 AT 8:29 AM
Tiny
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Sir, good morning. I was able to change the M2/6 motor but still hot air is not blown on the driver side. Before I had changed the blower motor resistor and also the heater control panel switch. Your advice will be highly appreciated.
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Tuesday, April 14th, 2020 AT 9:54 AM
Tiny
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Okay. So you have hot air on the passenger side but all the vents on the driver side are blowing cold? What happens if you turn the heat all the way to cold? Clearly passenger side is operating properly so it should be cold but I am wondering what happens to the driver side. Does it match the temperature on the passenger side or does it not change at all? Get warmer?

Depending on what happens with this, we may need to remove the actuator and plug it back in and change the temp. The actuator should move respectively. If it doesn't move then we have an actuator issue. If it does move, then we need to check the door inside the box.
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Tuesday, April 14th, 2020 AT 6:38 PM
Tiny
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Sir, hot air blows from the passenger vents, but, no air blows ( neither cold nor hot) through the driver vents. If I turn to heat all the way to cold the air flows through all vents -driver as well as passenger vents. Your advice will be highly appreciated.
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Wednesday, April 15th, 2020 AT 7:55 AM
Tiny
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Sorry for the delay. I guess I didn't understand the issue that way. If you have no air coming through any vent on any vent setting then I suspect you have an issue or restriction on the heater core for that side. The heater core has two sections or division for each side. This allows both sides to have different temps. I suspect you will need to pull the air box out and see what is wrong. If you have a borescope then you can stick the camera in there and see if the heater core is plugged but clearly we have an air flow issue on hot only and that really can only be the heater core.

Let me know if you have questions about this.
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Thursday, April 16th, 2020 AT 4:48 PM
Tiny
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Sir, first of all I thank you for replying me. The thing is that, I have cold air blowing through the drivers side vents, but when I turn the heat on neither cold nor hot air blows through the driver side vents.I changed the blower motor resistor and the heater regulator switch as well but no improvement. Your expert advice will be highly appreciated.
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Friday, April 17th, 2020 AT 6:24 AM
Tiny
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Okay. I understand. Here is what I suspect is happening. The air always passes over the evaporator which is what cools the air when the AC is on. However, when you turn it to heat, the blend door routes the air over the heater core. As you can see from the picture this is in heat setting and the blend door is allowing the air through the heater core which heat it. The second picture shows this. I drew a green bar where I suspect the heater core is plugged blocking the air flow.

The fact that you have no air flow on only one side only during hot air, you have to have a blockage on the heater core or in the air box.

Hopefully this makes sense.
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Friday, April 17th, 2020 AT 3:01 PM
Tiny
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Okay, I got you. So Sir what exactly I should do? How should I remove the blockage? Do I have to change the heater core or the blockage can be rust or debris? To be very frank with you I never done this job before. Hence your advice will be highly appreciated.
I have ordered an endoscope on eBay, but I will receive it after 15 May.
Sir, please if you can send me more photos so I can proceed with the job. Thanks a lot in advance. Have a blessed weekend, bye.
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Friday, April 17th, 2020 AT 5:34 PM
Tiny
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I have not done this job either on this vehicle so I really don't know what to expect. I attached the process and it doesn't seem too tough but again, they always seem easy on paper.

I would suggest removing it (depending on what you see with the scope) and just seeing if you can push air or water through the fins of the heater core. Not through the passage of the heater core where the coolant flows but where the air would pass over it. If you can't feel the air or see water flowing through it then clearly it is the heater core that is blocked. If not then I guess there is something in the HVAC box but I expect it is the heater core.
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Saturday, April 18th, 2020 AT 7:08 PM
Tiny
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Hi both, very informative posts thank you.

I have the exact same problem right now with my W203 C200 (MY 2002).

VIVEKHB - Did you find out why no hot air blowing on Drivers Side through any vents?

Mine is the same, Blows cold everywhere fine, but no hot on drivers side only.

Many thanks.

Gareth.
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Monday, June 15th, 2020 AT 2:33 AM
Tiny
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Hi Gareth, sorry to hear that you are having the same problem. But I have not yet resolved the issue as I am waiting for the heater core to arrive, in case it is blocked. Once I receive it I will dismantle the heater housing assembly unit and then do the necessary. May be the shipment is delayed due to Covid-19.
Once I resolve the issue I will let you know, bye. Stay blessed.
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Monday, June 15th, 2020 AT 11:43 AM

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