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D.I.Y ECM/ECU fan blower replacement

107K views 95 replies 30 participants last post by  bwind 
#1 ·
simple to check if yours has failed (this applies to any R170). open up the lid to black box compartment in engine bay where ECU is located. turn the car igntion to the ON position (2) but no need to start the car.

go back to the box and move your hand around the top (dont touch anything) and see if you can feel any airflow and or hear the fan spinning. if not it has failed.

to fix this, 2 options. 1 buy a new fan from dealer (a lot of $$ for something so simple), or 2 replace the electric motor inside. i found this one on ebay and confirm it works. simple to do with a person with some know how.

MM36 DC ELECTRIC MOTOR,HIGH TORQUE,12V TO 24V,FOR WATERPUMP,FAN,ELECTRIC CAR ETC | eBay

replace the motor and re-solder the wires put it back together and done. reason for the failure (i opened up the old motor) is basicly wear and tear the motor has reached its life cycle. given how many of you have this car and the age yours will or has failed.

cooling the ECM/ECU is important especially on left hand drive cars where the ECM/ECU compartment is near the exhaust manifold...

these few bucks can save you forking out thousands on a new ECU/modules....

please check yours!
 

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#2 ·
one thing check the polarity of the motor before your solder wires so its blowing from the outlet, and sucking from the center before you put it in the car. if its wrong just solder the 2 wires the other way around.
 
#3 ·
How to remove the blower motor?

Subby- I need to remove my blower to put a new electric motor in, but I can't see how to detach it (the complete blower+ housing) from the body of the module box, even though I have got all 3 modules out and the module box is otherwise empty. Does the moulded tube attached to the blower need to come out at the same time? I'm obviously missing something, and would be really grateful for your advice.
 
#4 ·
you can do it with all the modules in. the only module i removed was the K40 relay. (the one with the fuses in it).

slide up the big fuse (50amp) one on the side up out of the way too... undo the metal clip holding the top of the blower and pull up... as you pull up seperate it from the intake duct going to the blower and out it comes.

with the install lift the duct up as much as you can and as you start to slide down the blower pop in the duct and then push them both down
 
#5 ·
Subby,
I am looking at doing same thing on our 98 E320.

The motor speed of 14350rpm seems very high. My blower is a Bosch (APK 12V 0130002837) but it doesn't sound like it goes at that speed.

Later cars used a TYP RV40-18/12GU-013 13.2V. That seems a special model, but the RV40 series seem to run at 4500rpm (http://www.farnell.com/datasheets/73475.pdf)

Can't find specs for the Bosch blower
 
#6 ·
it will spin a bit lower once it gets under load (fan sucking from inlet).

it still draws little current so its not an issue... when you open up the box and put your face over it, it blows a LOT of air. with the box closed you can only hear a very, very slight "hum" if you like if your 30cm away from the ECM box in the engine bay

to me more cooling is better... this is about as close as your gonna get with an aftermarket electric motor without replacing the blower as a whole.
 
#12 · (Edited)
There is a circuit board inside my blower that feeds the motor. Incoming wire from plug connect across small component at bottom of picture. Did you keep this circuit board and do you know what it does?

ADDED: After a little research, it appears this would be an LC Filter to remove noise from brushes.

ALSO ADDED: Don't know about SLK, but on W210, housing mount for blower will only accept the old style blower with smaller diameter motor. Only fix other than a new blower would seem to be the motor replacement. It would be nice if we could somehow find that exact motor or one with similar specs. Has anyone found the specs on the Bosch blower?

I did find these motors. Seem close in specs to the Papst L fan?:

http://www.crouzet.com/english/cata...watts-1-4-w-Part number-82710001.pdf#zoom=100
http://www.crouzet.com/english/cata...watts-3-2-w-Part number-82720001.pdf#zoom=100

Haven't found anyone who stocks them :( Maybe Digikey will get me one? Do you think the 27.5mm one would fit?

 
#7 ·
Blower removal

Thanks for that, Subby- I just used brute force& got it out....but looking at it on my desk, I think it is different from yours in that the casing has been changed, making it difficult to get at the motor -photos attached, plus a 3rd photo showing how the motor is fixed into its casing by fixings not easy to deal with. Incidentally, with the foil covering the outer end of the motor spindle peeled off, you can see traces of what looks like spindle lubricant behind it.
Looks like maybe I'll just have to shell out for a new oem motor unit...:banghead:
 

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#11 ·
Thanks for that, Subby- I just used brute force& got it out....but looking at it on my desk, I think it is different from yours in that the casing has been changed, making it difficult to get at the motor -photos attached, plus a 3rd photo showing how the motor is fixed into its casing by fixings not easy to deal with. Incidentally, with the foil covering the outer end of the motor spindle peeled off, you can see traces of what looks like spindle lubricant behind it.
Looks like maybe I'll just have to shell out for a new oem motor unit...:banghead:
It looks like you have the Papst blower. You can buy one with similar dimensions but slightly different number at various on-line locations for $50-$60.

The original blower out of my 98 E320 is a Bosch 0130002837 (MB A2105450495) and it takes a motor similar to the UK hobby motor. I read that the blower for a 2001 E320 is made by Papst (TYP RV40-18/12GU-013 13.2V) and part is A2105450595. EPC says this is for E211. Papst make a generic almost identical blower with part numbers TYP RV40-18/12H or L which is less expensive.
 
#8 ·
yep diff manufacturer did that blower.

still might be able to hunt down an electric motor to fit. slide a thin screw driver under the impeller and try to slowly pop it off. you may be able to see screws which are used to screw the motor on to the casing?
 
#10 ·
blower motor--returned to ebay seller....

Hi again Subby- just to wrap this up for me, I contacted the guy who I had ordered the replacement motor from (the Ebay link you provided) and he immediately and without any hesitation agreed to cancel my order & refund my paypal payment! An ACE :bowdown: and I recommend him warmly to others.
 
#15 · (Edited)
New blower on the way

Couldn't locate the "L" in stock on a UK Web store, but plenty of the "H" type. There doesn't seem to be any difference in power supply specs between the two, just the L pushes more air through (and has shorter life expectancy:eek:)- so I have ordered one on-line for delivery tomorrow- cost about 20% of the MB list price:thumbsup: I reckon I owe you (AND SUBBY, for all the really helpful stuff he has posted on here over the years) a pint or two each:)
 
#16 ·
Took the motor out of my blower and it is made by Johnson Controls. I can't read the number properly but it seems to say 12V, 327 220 259, 362841. Do you see something similar Subby?

Couldn't find that number on Johnson's site, but they did have the motor in the pdf, which seems close. Next thing is to see if I can buy this motor in small quantities.

PS: Dunk -Hope the blower fits properly. If not, maybe you can switch parts to your housing.
 

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#18 ·
yep thats a top ebay seller.... yes i kept that little circut board, and my original motor said just "johnson" on it, no part numbers which i could see.

i did think about using other motors (but the ones which i found in OZ) were either too long or too short. and the small ones didnt generate enough rpms when under load to sufficiently cool such a large box. and they were only rated for 9v.

the larger motors were good (low amp and rated for 12v) but they were too long to fit in the casing. i could have got it to work, but would have meant customising it and a lot of mucking around

this ebay motor went straight in, no mods (no cutting or alterations) for the bosch blower!

i dont know about other countries but a replacement ECM fan from the dealer for this car is a lot of $$ for something so simple!
 
#19 ·
this ebay motor went straight in, no mods (no cutting or alterations) for the bosch blower!

i dont know about other countries but a replacement ECM fan from the dealer for this car is a lot of $$ for something so simple!
Lowest price I could find in Canada was $300.00! In USA, lowest was about $200. And all it needs is a little motor worth $5-$15. And Papst sell a superior blower for $45:confused:

If I can't get the Johnson motor shown in the pdf above, I may get this one:

QJT-360S-14280: NICHIBO TAIWAN CORP.: Electromechanical

They both have rpm in the same range as the Papst that MB now uses. Don't know for sure, but the Johnson is probably better quality that the Taiwanese one..

I checked and the Papst fan and motor would just fit in my housing, but not sure I could get the mounts to work. It is a much better blower with ball bearings and long life expectancy. The Bosch has bronze bearings and it seems on mine that that is the problem. They were squeaking and seize at times. I bought a spare from Germany that was DOA. Same problem. Fan runs fine after lubing, but can't keep doing that!

Anyway - this thread has been very useful for a W210 owner. Thanks for letting me in :)
 
#20 ·
Just another little piece of info:

BMW (and probably others like VW and Audi) also use the same (or a very similar) Bosch blower.

I found two BMW blowers that come with a flange that is part of their module casing. They cost $72-$129 on-line in USA. Parts 12907571019 and 12901438062. The connections may not match our cars. Need to compare them carefully. The motors are likely the same.

But, I am still going to change the motor on my blower.
 
#39 ·
Thank you Subby, LargeJohn, Bazzle, Leapyfish, Cacecef and many others for all your posts/knowledge. I've been lurking and fixing for several months now after buying the SLK 6 months ago.

I can confirm that the Radio Shack motor ($5.39 in stock 3 blocks away) seems to work just fine. I replaced it 2 days ago and have been running the engine and a/c hard in 93 degree Texas heat and it's still kickin'.

There is no telling how long the old one was dead, but it spun freely (3K+ ohms). I couldn't hear or feel anything running in the box. After I replaced it, boy you can hear and feel the vibration. It is a very powerful little motor. It showed 1 ohm and beeped for continuity whereas the old one didn't. The fan runs CONTINUOUSLY in my car with the key in pos 2 and sitting overnight.

I checked the K40 relay while I was there. It looked brand new and probably is fairly new. I don't have all the maintenance records but I think it was mostly serviced at MB in Georgetown, north of Austin. I wouldn't be surprised if the fan was "overlooked" for future business.

I had a hell of a time getting the male plastic wire plug out of the female connector box. For anyone in the future attempting to remove the entire wire piece from the motor back to the connector box, you have to PULL HARD, manhandle that sob. I thought the wires would snap before that plastic piece would come out, but they didn't.

Incidentally, a bunch of black powder came out of the openings of the old motor there. I don't think it came from the Bosch black housing but I guess it could have. Make sure when replacing the squirrel cage fan, that you don't push it all the way against the black inner housing. It might restrict the fan and burn up the motor. There is plenty of room to keep it away from both sides of the housing.

Thanks again for saving me many $'s Subby. If I ever make it down under, I'll buy you some pints!:thumbsup::D
 

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#22 ·
After reading all the comments on the blowers involved I determined that our later model SLKs have the Pabst unit which is a brushless device and has a very long life expectancy. Probably have no reason to get excited about it until maybe 900000 miles or so! As usual I jumped the gun and ordered the motor mentioned by Subby and now find I can't use it. If anyone needs one I'll be happy to sell it.
 
#24 ·
the only thing which can fail on the newer models is the bearings... they can dry up or sieze. so yes it will last longer than the older slk's but still need to check the fan is spinning! dont assume it will work forever

shame this fan isnt hooked up to any warning lights or check engine light upon fan failure etc... this could cost someone a new ECU!
 
#27 ·
My motors arrived today.

The Nichibo motor from Jameco is very similar to the Johnson, except it has vent holes on the outer face. (see pic below). I installed the new motors tonight in my original and another bad blower. In order to not totally block the vent holes, I cut notches in the foam donut that fits between the motor and the noise filter cct board. (pic below)

Before installing the new motors, I blasted the old ones with contact cleaner - a lot of black soot came out. After blow drying, I lubed the bearings with Teflon spray lube. I then tested the old motors and they ran fine.

I compared the sound of the fan with new and old motors and the new motor sounded a bit faster. Didn't measure flow rates, but they are not much different.

Next step is to install one fan and get my car back together!
 

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#28 · (Edited)
...simple to check if yours has failed... see if you can feel any airflow and or hear the fan spinning. if not it has failed.
You absolutely sure about that, Subby?:( I fitted a new pump, directly from Pabst (who supply them to MB for the 2002 cars at least), and was alarmed to find that the new fan did not run when the engine was started up:mad:. So while I had the car at the MB dealer in connection with other business, I had them check out the fan: the senior technician confirmed that the fan was in good working order (or so he said- no idea what steps he took to test it, though he only had it for a short time) and that he was pretty well certain they were temperature controlled, and that since the temperature that day was low- about 12*C- it wouldn't be expected to come on.
I referred him to what you said, and he said he could find nothing about it in the official documentation.
It'd be interesting if anyone else with a 2002 onwards 200 or 230K could be bothered to take a look and see whether their blower pump runs even when the ambient temperature is low:)
 
#29 ·
It'd be interesting if anyone else with a 2002 onwards 200 or 230K could be bothered to take a look and see whether their blower pump runs even when the ambient temperature is low:)
If you have access to a wiring diagram, that should show up any temperature control that may be present. I know that on my 98 W210, there is no temperature control and nothing to alert owner that fan has failed.
 
#30 ·
i can check WIS documentation but i believe it is always on. there is no mention of the temp sensor anywhere.

easy way to check get a multimeter and see that the 2 wires going into the motor get +12v when engine is running or key is in ON position. if it is getting +12v and motor aint spinning its failed.
 
#34 ·
if it is getting +12v and motor aint spinning its failed.
I agree completely with your comment that lots of electronics in a confined box is going to get hot quickly :( and that it seems highly likely that the fan should be on fulltime:mad:
Tomorrow I'll get the multimeter onto it and let you know whether there is voltage in the cable leading to it.
I did get a finger onto the fan in its housing, and it spins freely when pushed by a finger and is obviously not seized- can't believe a brand new pabst motor could be dead on arrival:eek:
 
#32 ·
i can check in wis but im pretty sure the system isnt smart to monitor the temp of multiple modules and then turn the fan on and off.

lots of electronics in a confined box is going to get hot quickly... it just may take a tad longer in a cooler climate but once the engine is at operating temp the radiant heat of the exhaust manifold will get things hot quickly on LHD cars. on RHD cars like in OZ the ECM box is on the other side away from the exhaust manifold so it may not impact it as much...

reason fan is there because the ECM modules are in the engine bay if they were inside the car (if they could find a location) they probably wouldnt have a fan. its to combat radiant heat of the engine bay compartment to keep the modules safe opperating temp at all times.
 
#35 ·
if you can take the motor out and unplug it and measure the resistance across it to see if its OK.

if your multimeter supports it you can do a continuity check. multimeter will buzz/beep indicating a complete circut on the motor side.

also hook up a voltage source to it direct *while blower is out of car and not connect to ECU) and see if it spins or trys to spin with the help of your finger moving it.

then measure the wires with it plugged into the ECU and you will see they will read +11.3 to 12v when key is at ON position both engine running or not running.
 
#36 ·
....hook up a voltage source to it direct ... and see if it spins..... then measure the wires with it plugged into the ECU... they will read +11.3 to 12v when key is at ON position both engine running or not running.
Thanks for that, Subby, so I took the blower back out of the module box and hooked it up to 12 volts, and it whirled away beautifully :)
I then stripped a small section of the insuation sleeve from both the wires from it to the connector at the CCM (Multi-function Control Module) so as to be able to meter them cleanly for voltage & reinstalled the blower, reconnected the battery, switched on the ignition fully, but there was no movement at all from the blower fan, and when I metered the wires just to be sure, there was no voltage there at all.
So unless there is a fault in the CCM (and none showed on the recent Star diagnosis) maybe power to the blower is off until switched on per some electronic trickery in the CCM :(
Thanks also to Firm for your comment- maybe this was a change at facelift time, which I think was between 2001 & 2002:confused:
 
#37 ·
had a look at WIS no mention of any temp related sensor?

pre face lift was up to about mid year 2000 and use the m62 clutched supercharger and Bosch engine mgt system

facelift was late 2000 onwards and uses the smaller m45 non clutched supercharger and Siemens engine mgt system

if Firms 2001 model (face lift) runs all the time im guessing yours should too? :confused: might be worth while unplugging it at the plug (to test voltage at the plug) to make sure the wires that run to the fan dont have a break in them?

if your multimeter has a thermocouple probe (temp sensor) place the sensor in the box and gently seal the box and watch the temp on the multimeter after a while... it gets quite warm with no air circulation
 
#38 · (Edited)
...had a look at WIS no mention of any temp related sensor?
Yeah- there is certainly not a free-standing temperature sensor in the module box:confused: The only possibility might conceivably be a trigger of some sort in the CCM's firmware, internally activated when the circuitry gets over heated. I understand from a supposedly expert source (but not someone I know well personally) that the post face-lift CCMs were different in at least one big way- the indicators were no longer activated by a mechanical relay, but by solid state electronics, as they had become so notoriously troublesome (though I see that there are still 4 hefty relays on the later CCM boards!)
Back to my case- the original blower motor when I checked it was seized solid, and you would expect that to have drawn attention to itself by blowing a fuse somewhere, or flagging up some kind of symptom:(but there didn't seem to be any at all!
I'll do as you suggest, and disconnect the blower plug from the CCM and use the
multimeter to see if there is voltage there with the engine switched on (tho' when I'll get round to doing so I'm not sure, as the boss is getting peeved at the amount of time I'm spending out in the garage:cool:)
 
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