There is another way to replace the blower motor regulator in pre-facelift W-210 that doesn't require buying a regulator for the W-140 and splicing it into the old wiring harness.

K-A-E makes a blower motor regulator (resistor is their term for it) that is a direct replacement for the old style that is no longer available from MB. It is part # K-A-E 3.701.420. Although the base plate of the regulator is slightly larger and differently shaped from the original part the screw holes line up perfectly and and the wiring harness is direct plug and play into the original motor and chassis wiring harness.

Put one in my '97 E320 a couple of years ago and no problems since then -works perfectly.

Got mine from All European Auto Supply
http://www.alleuro.com/

 

There's a seller on ebay that is selling what appears to be the old-style regulator with the correct harness (meaning no cutting/splicing), and it's only $49.99. Anyone have experience with this? (Search ebay for item #370609227648)

 

I ended up purchasing the Bosch regulator from Europartsdirect for $124, and it came with two harnesses: one for the S-class and one for my E320 -- meaning, no cutting/soldering necessary! Highly recommended!

 

A fond hello to everyone in this most worthy forum...

WOW! Finally able to post! Been reading and reading for weeks now on different things...

Ok, I have replaced so many things on my late 97 E320, its almost getting ridiculous.

Just another $400 + in parts I have to secure...

As stated above, I have a 1997 E320, and I now need to replace the blower regulator. My VIN is xxxxxxx+ 418,548. WHICH blower regulator do I need?

Since owning this vehicle 6 months ago, I have replaced shifter & tranny grommets, tore apart and cleaned up shifter, drivers side power window guts, spent $126.00 to diagnose faulty passenger front brake line, replaced EVAP container, over $600 + mechanics time, $85.00 (parts ONLY) oil change have a leaking seal in front of engine, have swapped out the center console for the windows & trunk $100 +, and now need to replace the blower motor relay!

MY GOODNESS!!! I thought a Mercedes is a QUALITY vehicle!! I have had more luck with my FREE donated '92 MOPAR MiniVan that I have had 2 separate deer commit suicide in front of!!!

And I have not yet gotten to the paint job needed on the fickle thing, or the new sneakers all the way around!

Needless to say, I have to address the useless sunroof eventually, and the ever faulty lights all the way around on a consistent basis!!!

This car is like a high maintenance B I T C H! Great to look at, but pain in the **** to have parked in your fav spot.

What more do I need to do to get this female ready for a regular leisurely cruise? Its like there is some little deutsche leprechaun up there that I must have pissed off at some time in my not so distant past. Kinda like I am the rainbow, depositing this real and tangible gold into a fictitious pot that some twisted and fatal act of inconsideration is doing its monkey best to prevent me from actually enjoying this car!

I SWEAR it was previously owned by a female that hates ALL men, just because the men have no concept of hormonal displeasure, but wishes in her insane way to spread the displeasure equally to each and every happy human being!

phew... I'm back now. After all that being said, does anyone know which blower regulator I need to cool off with?

 

What a great thread! And thank you Tony and so many others that help with the flow of information. The Internet is a wonderful, amazing thing. Its too bad so many are still ignorant of what an important and useful tool it is!

1997 E320...

After looking and searching for the right part for me, I chose the cut and solder method to save almost $170.

I purchased the # 1408218351 for $69.95, at http://www.importecwarehouse.com as opposed to the "Plug-n-Play" one (#3.701.420) I found at http://www.kae-automotive.de/KAE_Gmb...estellung.html for 189.00 € ($238.89 at todays currency conversion). I figure I can splice a few wires for $169.94! I also ordered the 2 cabin air filters for $25.90, so a total of $95.90 with FREE SHIPPING!

I found another 1408218451 at http://www.autohausaz.com/search/pro...ber=1408218451
for $134.89, which is a BEHR.

(I hope the one I got is not a French or Chinese made imitation! I will advise...)

Please note! This is for my 1997 E320. As a note says on the Importec site, there is another one for yr 2000 + models for $119, seen on their front page, or at http://www.importecwarehouse.com/Mer...2108211551.htm
and says "PLEASE NOTE: THIS IS A NEW STYLE (for models 2000 onnwards) BLOWER REGULATOR WITH A MALE CONNECTOR PLUG, IF YOU HAVE THE OLD STYLE, PRE 2000 BLOWER REGULATOR WITH A FEMALE CONNECTOR PLUG, YOU WILL ALSO REQUIRE A NEW STYLE 2108206842 BLOWER MOTOR & 2108352740 COVER, IF IT HAS NOT BEEN UPDATED ALREADY."

I hope this is of some assistance to others, as I have been helped by so many on here.

Thanks all! I will update after I install...

Lefty

 

Lefty, you got a car two years too new. You shoulda bought a W124 instead of a W210! But that's getting off topic...

 

After reading Tony's DIY on the W210 A/C problem I dove in like the rest.

The short version:

1997 E320 150,000.

A/C stuck on LOW regardless of indicator position.

Called Autohaus AZ for the Behr1408218451 resistor, which is $134.89, but OUT OF STOCK! So I pulled the trigger on the Kaehler 1408218351 resistor, which is $142.49. Add to that a soldering iron, some shrink wrap, dielectric grease, and solder for another $20.

Followed Tony's DIY to the letter and VOILA -- this fix is brilliant.

My ONLY problems were as follows:

1. I'm a big guy, 6'1 - 243, so bunching myself under the dash to get everything out was challenging, but not impossible.

2. The plastic heat wrap on the biggest wire (the black one) didn't quite make it over the entire soldered joint in the end. I compensated with electrical tape. Red and yellow were fine.

3. The black wire was difficult to strip. I was afraid I took too much wire, but in the end it was fine.

4. I needed to practice my soldering on a dummy wire. It's easy to get the hang of. If it was a circumcision I would worry. The wires survived.

AND THAT WAS IT!!!

I was quoted $750 at the local shop to fix resistor and replace motor. Crooks!

$165 did the trick. It's so easy and well worth it. THANK YOU TONY!!!

 

Hey again folks...

As I said I would update after install.

Well, I got my part from here, part # 140 821 83 51. It was considerably less expensive ($80 - $140 less) than other places.

I also got the cabin filters, and after delivery, it was all under a hundred bux.

COOL! I read "Stealership" horror stories for over $1200! Thieves!

Well, heres my story... About a yr ago, some young puke pulled out in front of me while he was talkin on a cell phone, and screwed up my neck & back fairly severely. Had surgery +++ in the last year.

I could NOT in any way get on the floor of the car, upside down and get to where the replacement needed to be. Impossible for me. SOOOOOO... I asked my GF to do it! Well, my GF is 4'11" and about 85 lbs. I showed her Tony's photos and instructions, gathered the tools he suggested, and grabbed a shop light, headed toward the car with parts in hand.

She started pulling screws (sorry boys, I wont share photos of her upside-down, in shorts, on the floor of the Benz, with a... never mind...), and in about 7 minutes she had the blower motor out! This is really the first time she had ever been upside-down, un-screwing, if that makes sense.

Now, understand, I needed to explain EVERYTHING in the pictures to her, from the difference between a TORX screw and a Phillips head. My point here is the actual simplicity of the removal following Tonys instructions. If you are worried about it, DONT BE! Just go for it.

OK, cool, I have the blower motor in my hands now! I continue to follow the instructions to the letter, and cut (BIG YIKES) my brand new $70 buck part! Soldered and used shrink wrap (not my first BBQ here) and put it all together as described by Tony.

Well, here it is, a much simpler fix than I imagined, yet not installed yet. Uh OH!

So, I asked my tiny tiny asian GF to put the unit back where she pulled it out of 35 mins earlier!

Now me being 6', 230 lbs, and recupin from neck surgery, this was a life saver and a necessity!

She mounted it, screwed it, and finished the job with a smile, a satisfied successful kinda smile (I like it when she does that!).

I then started the car, and had was happily happy with the happy ending I got with my blower blowing beyond expectations. My hat is now in the back seat!

If anyone is worried about this mod, its easy and cheap! Just follow the instructions, dont over-think it, and you will be happy with the results.

Great job Tony, and a HUGE Thank You!

I actually was so impressed with the results with her help, I couldnt resist changing my shifter as well on this fickle E320, but thats for another thread in this forum. Her talents are expanding...

 

1996 W210 Mercedes 300E Diesel VIN 210020 2A197603

Removed the old faulty blower regulator which uses three wires from the harness and replaced it with a new four wire unit. - see this PDF for the full story. The small red wire goes to 12V. Involves some machine work on the old heatsink.

 

I really appreciate the DIY and your detail but after reading so many posts, I cannot figure out what I need to buy for my car. I have the weak blower deal going on all all esle seems to work fine. Can you tell me which regulator etc I need. When I go to Autohausaz.com this is what they state:

<TABLE border=0 width="100%"><TBODY><TR><TD vAlign=top width=100>2108211551



</TD><TD vAlign=top>Behr OEM
Blower Motor Resistor/Regulator; Late Version with Male Connector
If replacing original 2108206110 or 2108212951 regulator, also need 2108206842 blower assembly and 2108352740 mounting plate/cover. Changing the connector plugs does not make old blower assembly compatible with new regulator. 1 per car.


</TD></TR></TBODY></TABLE>
I type in the additional parts and they do not have them in stock. Also, I don't see where anyone is needing those additional parts. Please help...it's HOT AS HELL!!!!!! Thanks in advance. Much Appreciated...

 

SAH44

Can you post a photo of your faulty regulator? Looks like my post above yours (PDF) replaces the part number you have quoted (210 821 15 51) - however it requires some machining of the heat sink. I guess that a flat aluminum plate would do the job. The later regulator seems much more efficient than the original. Maybe it uses pulses to control the current to the blower instead of just dissipating the volt drop as heat.

 

is there a diagnostic in the a/c that will tell you the voltage at which the regulator is operating? I feel like mine blows on close to max but probably not completely. I have 99 E320.

 

First off GLAD your blower is working now, i know how sweet of a feeling it is when you turn the switch on and it blows full blast !!!

We need to get "royalties checks" from this person for using our "advice/instructions" !!! haha

 

I don't know who it was, but somebody on one of the thread about the fan motor posted and said, and I'm paraphrasing, "Before you buy anything just wiggle the wires on the fan motor to see if that does anything."

This is exactly what I did while I had the AC and the car switch on. My problem turned out to be just that. Nothing wrong with anything else.

So many thanks to the guy who took the time to post that tip and if you are ever in my area of Fairfield county, Connecticut, I want to but you a couple of beers.

Much appreciated.

Jesse

 

Okay so I've read all the posts that point to the regulator being my problem, blower motor working intermitantly. So I buy a new regulator, remove and replace it (it was plug and play) and now the blower motor stays on all the time, even with the key off. All the posts I've seen say the regulator is the problem but, this is a new regulator. Assuming the part is not faulty, what would cause a the blower motor to stay on with a new regulator?

 

I replaced the regulator last year. Everything was fine for a while then the blower motor quit. The brushes were shot but I found someone who replaced the motor brushes and the blower worked perfectly until 2 days ago. The motor is down again. It will run if you manually start it but it won't start on it's own and it doesn't run as fast as it use to when you get it running. My brush replacement person seems to be MIA, so I have been looking for a replacement blower. All the parts places (i.e. AutohausAZ) say that I will need a new regulator for the new motor. Do I need another new regulator? And they say I also need new mounting hardware/frame. Really???? Arghhh. Help...

 

hi,
At this moment these regulators much cheaper on eBay around $40.
I bought one, it works OK on my w210 1997, and comes with thermal paste.

 

I went to two places and the prices ranged from $650-$1200 to fix my ac. My ac wouldn't come on at all. Luckily one of the shop guys said that when they grounded the fan it ran. After searching the internet, I came across your thread. Dude, I read your post, ordered the part from autohaus, watched a video on soldering vs. Crimping, bought a soldering iron, and one day later "chilly ***** " in my cabin. The pictures helped a lot. If anyone's thinking about repairing their own, go ahead and just follow the instructions step by step and you'll be fine. Thanks for the post dude.

 

1996 E320
There is a replacement Regulator that Bosch (German made) makes that has both harnesses, the short one that you need to splice and it also comes with a long one that is a "plug-N-Play harness. Just un-clip the short harness at the regulator and plug in the longer harness, plug the red and the blue wires to the motor and plug the box shaped plug into the system.

Now the regulator that went bad seems to have been replaced with a regulator made in France at some time. The new regulator is larger than the French one by almost twice the size. It fits and all the wires are correct. Just to make sure that all the wires got plugged in right, I compared the two side by side with the bottom that I marked "B" using a silver marker. I don't know if one can plug it in wrong but I didn't want to take the chance.

It's been a few days and it appears to be working well. Best of all, no splicing! Install is about 20 minutes without splicing. Bosch part number is 9 140 010 512 BTW, I am not affiliated with Bosch in any way, BUT I sure do like the way they think! Part runs about $150 depending on where you get it.

Special thanks to my mechanic who ordered the part for me

 

I posted further down the same results with Bosch! Let me add that I own a 1996 E320 and the Bosch part is 9 140 010 512, Now a 20 minute fix!

 

1996 E320 Benz
There is a replacement Regulator that Bosch (German made) makes that has both harnesses, the short one that you need to splice and it also comes with a long one that is a "plug-N-Play harness. Just un-clip the short harness at the regulator and plug in the longer harness, plug the red and the blue wires to the motor and plug the box shaped plug into the system.

Now the regulator that went bad seems to have been replaced with a regulator made in France at some time. The new regulator is larger than the French one by almost twice the size. It fits and all the wires are correct. Just to make sure that all the wires got plugged in right, I compared the two side by side with the bottom that I marked "B" using a silver marker. I don't know if one can plug it in wrong but I didn't want to take the chance.

It's been a few days and it appears to be working well. Best of all, no splicing! Install is about 20 minutes without splicing. Bosch part number is 9 140 010 512 BTW, I am not affiliated with Bosch in any way, BUT I sure do like the way they think! Part runs about $150 depending on where you get it.

Special thanks to my mechanic who ordered the part for me

 

Looks like Bosch 9 140 010 512 is for most W140 models, equivalent to MB part # 140-821-83-51... based on some Google searching. YMMV, etc.

http://www.ebay.com/itm/120960679357

 

UPDATE:
So what I thought was a loose wire was in fact failing blower motor brushes. I pulled the blower motor, very easy I might say, then put a spacer behind the old brushes to give the spring more tension against the brush. This worked well for over a month. Now, 3 out of 5 times it does not come on EXCEPT when I hit a bump in the road, then the fan comes on normally. That guy you saw actually steering into that pothole, that's was me.

Besides being as stubborn as I am, I still think the problem is the brushes NOT the regulator so before I break down and spend the money for a replacement assembly I'd like to ask if anyone here has replaced the brushes in the blower motor OR knows the actually physical size in MM or IN of the brush.

The guy who wrote the original comment about the loose wires was suppose to email me when he passed through but I never heard from him so I hope he got to and from his destination OK.

Thanks,

Jesse

 

Had to laugh when I read this. I used to go looking for pot holes myself. I found an old school repair shop who could replace the fan motor brushes. I worked fine for about a year and then stopped working again. When I went back, they were no longer in business. I bought a used fan motor out of another car.

 

My heater blower on my E430 (2000) suddenly switched itself to full power. I ordered a new regulator (ebay for £42) fitted it and it all worked perfectly. I then drove the car and it worked fine, but after about 20 miles the same fault re-occurred, blower full on! Does anyone have any thoughts on this problem please?