E320 Heater Blower problem

[phoenixmark]

I have a E320 (w210) 1996 model straight 6 petrol Auto with climate control air con. The heater blower will not opperate at full speed only seems to run slow even when you push the windscreen thaw button. Any idears how to fix it? Cheers.

 

[jberks]

At that age, I'd supect the fan brushes.
As a starter for 10 have a look at http://forums.mercedesclub.org.uk/showthread.php?t=32261&highlight=fan+brushes
Do check the voltages as the regulator can cause similar symptoms but the brushes are the most likely candidates IMHO.

 

[phoenixmark]

heater fan blower

Thanks Jberks how do I find the fan motor the link from bob the builder does not connect.
Cheers

 

[Aussie Nick]

The fan blower is located under dash behind the glove box i suspect as 202 c class. I have some posts under my user name which may help you and save you money.Trace through my posts ,you should find the relevant ones relating to a rebuild of the fan motor if it can be done on yours. Mb charge a premium for the blower. Do not readily accept advice that the blower cannot be rebuilt, it can in some cases. You need to pull it out and see if the brushes can be removed and replaced.If they can remember that they will need to be pre-bed in to shape to make good contact with the wiring loom assembly before they will work.

 

[phoenixmark]

Heater blower problems

Thanks Ausie Nick.

Just a Thought, The fan is working but only ever on slow. So presumably the brushes are OK. Could it be a heater relay? If so where is it. I've looked in the fused boxes but cant see it anywhere. It does state it is number 20 but there is no number 20 in the relay box (in the engine compartment in front of the steering wheel area.

Cheers

 

[Aussie Nick]

No it wont be the relay. It could be the regulator which is attached to the fan motor. You will need to pull the motor out to find the regulator. It could still be the brushes on their last legs. Pull the motor out it is not hard . If i recall there are 4 phillips head screws to undo . Hold onto the motor as you undo the last threads as it may fall on you and it is heavy.Suggest that you ensure the fan is totally on the off position before you start undoing. As a precaution I would disconnect the +ive lead from battery. I suspect strongly that the problem is either the regulator or the brushes.If the regulator is on the way out the brushes are not far behind.Better look at the whole lot now and have to comeback to this area in the near future . Keepus posted as to your progress

 

[television]

You can check the control unit by measuring any change in the voltage when you change the speed, if it is a press button control unit the switches do get dirty and can be cleaned

You measure where the wires go onto the regulator

 

[Johnny 74]

same fault ?

I am not sure if it is the same fault , but my heater blower fan would only run slow speed , I was advised my a member on here to remove the pollen filter ( located under passenger glove compartment .) . for me it was great advice because as soon as I removed the filter , blower speed was back to normal ... I then purchased a new filter . Thanks for advice .By the way I have a W210 Mercedes E class
Johnny

 

[JimM]

Yep, my fan seems to run slowly on max, but it does step up through all the speed settings when I set each speed manually.

And there is little air flow. About half of what I would expect on max, and the fan sound is also about what I would expect at setting 3.

So rather than brushes right away I will opt for the pollen filters first.

One of our vacuum cleaners does the same, when its filter is blocked, the motor runs slower than max.

Thanks to all here and elsewhere for all of this great info! :mrgreen:

 

[television]

Usually when the fan only runs at a slow speed only the regulator pack has failed, they are on Ebay, but beware of fakes, they are screwed to the fan motor housing using a heat sink paste.

 

[baznbev]

Hello, I have noticed you kindly sent out info on replacing thermostat on w203/ C160 and wondered if you could send to me please.
Thank you
Barry wood

 

[television]

Please activate your E mail

 

[JimM]

Update:

I finally replaced the pollen filters (2 on my car) and yes, they were very sooty, and yes, my blower now runs at full speed.

So there is some kind of sensing to stop the blower running at full speed when there is low airflow e.g. when the filters are blocked.

The job only took 10 minutes once I knew about the 2 hidden screws and that the glove box needs a huge tug to get it out.

So I wrote a photo-guide on how to do it, as a "thank you" for all the help I've received here, to help others.

The permitted file size on this forum is too small so I could not attach it.

Here it is, please download a copy to your PC because I'm not sure how long my kind hosts will continue to offer this free facility: http://www.fileswap.com/dl/4VBhLGL8y/W210_E320_Pollen_Filter_replacement.pdf.html

Thanks again.