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96 G300DT
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Discussion Starter #1
The fan in our E-class is suddenly slow. No unusual noises, it just seems limited to about half speed. The LCD bars keep going up on the environmental console as you push the fan toggle. No extra blowing though.

Is fan power still managed with a resistor pack? A blown resistor would explain the failure. I would imagine these newer computer controlled cars would have a more sophisticated motor control.

Any hints would be appreciated.
 

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1997 E420 Sport
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262 Posts
Well, seems like your blower motor control is bad, not the in dash A/C control but the one attached to the motor itself.
I had the same symptoms, so I changed mine a few weeks ago. Problem solved.
The bad news is that for a W210 you have to buy THE WHOLE MOTOR unit.
The good news is that you can get the blower control of a W140 which is the same except for the length of the wires. Nothing that a good soldering can´t take care of.
Do a search on this forum and you will find many posts about this common malfunction.
By the way, get the "made in Germany" control unit, not the one made in France.
I got mine from Arizona auto parts, sponsor of this forum. Great prices and service.
 

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96 G300DT
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Discussion Starter #3
How do I access the fan? I know where the filter is but don't know how to access the blower.
 

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1997 E420 Sport
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If you know how to access the carbon filters, you know the access to the blower.
Below the glove compartment (not behind, where the dust filters are)is a plastic cover fastened with screws. After you remove this, you will see the doors for the carbon filters to your left and to your right you´ll see the aspiration port for the blower. Remove the screws and the motor will drop. The control is attached to a metal plate on the motor itself. It is a square device, 1x1.5in where the wires (black, yellow, red and blue) end, fastened with two small screws. Remove, open the cap, with a soldering iron remove the wires and resold new unit.
Be careful to clean well the contacts as well as the metal plate where it attaches. Heat transfer grease comes with your new unit and is vital to the life of the control, so be careful not to waste it.

The part # in Autohaus Arizona is 140 821 83 51
 

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96 G300DT
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Discussion Starter #5
Sucess!

Thanks Rafael!

I bought the W140 part. Prying off the plastic caps on both units allowed me to solder the wiring harness from the old unit onto the new unit.

Anyone contemplating this job should note that the pins have changed positions over the years. A high wattage soldering iron is a must as the pins should not be heated for long.

Aside from having to lay upside down in the foot well for the install this was an easy job.
 

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1997 E420 Sport
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262 Posts
Next time [:p][:D]take the motor out. Just four screws. Detach old control unit and atach new one while the motor is out. That way is a very easy job. Hopefully you won´t have a "next time" as the new unit should last long.
Glad to hear you have full blowing motor again. [;)]
 

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02 G500
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Rafael: thanks for the tip. Our 98 320 fan slowed down last week - I replaced all the filters, but no change. I will order that part and pull the fan out and replace it. I assume the the color coding will make the soldering to be done obvious?

Steve
 

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96 G300DT
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Discussion Starter #9
Rafael Grullón - 5/6/2005 8:47 PM

Next time [:p][:D]take the motor out. Just four screws. Detach old control unit and atach new one while the motor is out. That way is a very easy job. Hopefully you won´t have a "next time" as the new unit should last long.
Glad to hear you have full blowing motor again. [;)]
Hey! I resemble that! I do a lot of dumb things. But I did do the work on a bench. I was muttering about having to lay upside down to get the fan in and out. One of the torx screws was quite uncooperative.

Now on to the G300DT which has worn out wheel bearings. A tough job on a clean G. Those parts are just welded in there with nine year old Austrian road salt. It appears that the PO let the grease in the axle balls run dry, letting in water.
 

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10 GLK 350 4Matic
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Rafael, that's great. I was just trying to figure out why I was having -- just this week too -- the same problem as Alan.

Where? who has the parts? Is there a recommended pusher?

A million thanks.

OK, I decided to read the post carefully - and I see Autohaus Arizona. They have a couple different parts with a very similar number they offer ( Behr for example) How did you pick the right (German) unit? The Behr unit looks like a different flavor on a similar or substitute unit??[:D]
 

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Well, after the last post I went out and did some testing. Looks like it starts out at full speed for around 30 seconds to a minute, then drops down to 1/2 speed ( wayyyy too soon) and will usually stay at this low speed no matter what you set the temperature, or any other settings ( auto, non/auto, hi speed, lower speed, defrost, etc).

Interestingly it will sometimes suddenly speed up for a few seconds -- then drop right back down to medium or low or whatever it is defaulting to ( always the same low/slow speed).

It's keeping me from burning up in our sudddenly Summer weather, but just barely. It's not real fun.

Ideas? same problem? Help![V]
 

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1997 E420 Sport
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No doubt. The control is going bad.
I took the less expensive from Autohaus Arizona because of the shape, which is the same of that my car had.
So far so good.
Let me thank e-klasse who advised me when I had the blower control unit problem. He is the one who deserves the credit of the W-140 tip.
 

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Autohaus Arizona seems to sell two units?

Did you get that exact part number? what about the alternate?

You said you managed to get the German unit.....
 

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Hello guys, in our E class we have the same problem. I havent bought the regulator yet, but I found out one thing with this failure. Its seems to be Voltage dependant. If the car is running (dynamo charging) the failure is there. With engine stopped it works ok. If the voltage to the regulator is lowered with diodes in series with the fan/regulator it may work ok.
 

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02 G500
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Rafael: did your fan fix this morning - took about 1/2 hour. Works great!

Now, care to offer a fix on brake lights that burn out monthly? I have used every brand of bulb I can find, including ones from the Mercede$ dealer. I replaced the purple socket, and that helped - I went two months without replacing the bulb.

Any thoughts?

Thanks,

Steve
 

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02 G500
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Rafael; thanks. Now all I have to do is replace the foglight and tow hook cover that recently fell victim to a truck tire tread, and the car will be 100% again.

Steve
 

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1998 E320
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50 Posts
I thought a pair of photos might help. Also, if I were to do it again, I would not solder the connections. It requires a lot of heat to warm the wires (they are about a 8-10 ga wire). Instead, a butt splice with dielectric grease would do fine. It might also avoid any overheating of the control module during the soldering process. Another benefit is that it really cuts done on the chance splicing the wrong wires together if the pvc jacket is left in place.
 

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