Early W210 Blower Motor Regulator Replacement DIY Here...
Cheers from Ireland.
My search results: Here are the two parts I found at Autohaus:

I thought I'd post my experience to let other know that installing the KAE part is almost exactly the same as installing the Behr part.
The only difference is the KAE part did not come with the two torx mounting screws, so I had to reuse the originals.
Also, the KAE instructions say not to add any thermal paste. The instructions say: "The surface of the KAE Blower Control Unit is already pretreated with a very high efficient propper (sic) amount of copper-heat-transfer agent, protected by a plastic cover." The package included a small cloth to clean the old thermal paste off the blower assembly
The instructions: With typos.

The shipping package. This blue box arrived inside a much larger brown cardboard shipping package. It was well packed, surrounded with brown paper to absorb shipping-shock and arrived in good condition:

Kaehler (KAE) part number 1408218351: The KAE unit with the plastic still covering the heat sink. When I was soldering the wires together, I accidently touched the plastic cover and melted a small hole in it. Fortunately, the plastic didn't melt onto the heatsink itself.

Cleaning the surface. I used the blue cloth provided to carefully clean off all the old heatsink paste.

The finished project. After reinstalling under the passenger side and turning on the blower full-blast, it worked great! Thank you for posting these DIY instructions, you saved me hundreds of dollars, and I now get full power from the heater and A/C.
i would like to say that the DIY here for the benz was the greatest money saver i ever had in a long time, it was easy to replace and only took 15 mins and saved $600....great pics and explained very well...keep the site alivethx tony
I had my mechanic do a "Temporary fix" so the A/C when the two wires (larger white connector and smaller black connector) were connected would blow only full blast high. It would continue to blow even with the car off or with the A/C electronics off. It worked for a while until I was driving and I smelled melted plastic. The larger white connector was starting to burn up and one of the metal prongs came out. If i read this DIY properly I need this wire to be functioning... What should I do next?
thank you in advance!
Jason
1997 E320 90k
Well, had the problem too. Followed your instructions.
I used the Behr (original part# 5HL 351 321-021; which is the same as 140 821 83 51). Search the Behr-Website at http://www.behrhellaservice.com/Channels/Home/Home.jsp
Great stuff !!!!
The first problem will be a pain to fix if you melted the connector on the car-side of the assembly. You can see from the photo below, the connector that comes with the replacement part is not the same. So you can't use that. You'll have to find a replacement that matches the original.

Hopefully, the connector on the car-side is still good. If you only melted the connector attached to the blower assembly, then you don't have to do any work under the footwell. All you have to do is find the exact same replacement connector (I'm not sure if you can buy the connector by itself) and include it in the project when you replace the blower regulator. Make sure the wires match.
Unfortunately, if you melted both sides of the connector, or if you can't find the exact same replacement, you are going to have to do some electrical work lying upside down on the passenger seat looking up into the footwell. Its already hard enough to disconnect and reconnect the existing wiring in that position. But having to splice in a new connector will be even harder. At least you don’t have to find the exact same connector.
This next part sounds obvious, but is critically important: make sure the replacement connector has the right number of electrical leads, and the same or better gauge wires. Make sure you exactly match up the wires coming from the car and going to the blower assembly to duplicate the original, otherwise you'll burn out your blower assembly.
The second problem seems simple but don't discount the importance of having wires that are just long enough, but not too long to reach their destinations. The original wires are just the right length so that the white connector from the assembly lines up with its counterpart on the car. If you replace them with wires too long or too short, you will also have a difficult time routing the wires around the blower to make the connection meet its counterpart. This will stress your splices, and the wires may interfere with the moving parts on the fan. So if you need to replace the existing wires, be extra careful to make sure they are as close to the same length as the originals.
Your DIY is going to be more difficult. I hope this helps.
The Best of Mercedes & AMG
If anyone can think of any additional info I would greatly appreciate it.
Jason
Here's my question: is a 1999 E430 a late W210? And if it is, I'm unsure how the process would differ.
Thanks!
Here's my question: is a 1999 E430 a late W210? And if it is, I'm unsure how the process would differ.
Thanks!
Good luck!
Last edited by tony; Mar 28, 2007 at 11:30 AM.
Enjoy
Iwhite: I believe that you have a '96 E320 just like what I have. Please tell me which part # that you replaced (Blower motor regulator only? or do you have to buy blower assembly and mounting plate as stated buy autohauaz.com). Thanks
Just got the part and did this repair this evening. Thank you so much. It works beautifully. My indie machanic wanted $1000 to get this problem solved. (new Blower = $450, voltage reg = $250, balance labor). Thanks to you and the folks at autohausaz, I am back in business for $163.63 !!!
A few questions for the group:
1) I noticed a lot of carbon dust from the motor brushes. Anyone ever need to change the brushes on these W210 blower motors ? Tough job ? Where to get the parts. Mine is working fine, but its always good to know.
2) Looks like the original post is a year old. Is everyone's new regulator holding up well ?
Thanks for helping me save my family $836 !
I'm glad I've been able to help everyone out. I won't be checking the board much anymore since I sold my E. You can catch me on the e38 board on Bimmerboard.com where my username is Imolatony.
Oh and tshaw, I happen to live in Norcross too. Small world, isn't it?
Cheers!
Last edited by tony; Jul 21, 2007 at 09:09 PM.



