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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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#70 ·
I just wanted to thank you for your information. I have an older post on here of my Radio Shack fan motor replacement. It worked for about 2 years here in Texas but burned out around 10/2014. I bought another R.S. fan but noticed your post after rereading this thread. You are correct about the longevity of the R.S. motor.

I just ordered 3 of these carbon bushing motors. I figured $8 for shipping spent anyway, so, ya' know. I hope they work for longer. We shall see.

Thanks so much!
 
#71 ·
oh just to mention again for the above motor it comes with a capacitor bridged over the 2 terminals. this must be chopped off as you will be using the filter from the factory motor housing.
 
#72 ·
I did mine this weekend, the oem had failed, it was likely to, with all that debris on it and around it. We hit about 40C here, so it was a must, that it couldn't wait.

Anyway, for anyone wants a direct replacement the motor is Bosch 1397220259 with dimensions 27mm diameter, 32mm long with 11mm long and 2mm thick shaft.

I bought this 2mm Diameter 15mm Long Shaft 3050rpm Output Speed High Torque DC Motor 12V | eBay with 24mm diameter, 31mm long with 15mm long and 1.8mm thick shaft @ 3000 rpm
Totally different dimensions but I fit it good and stable. It sounds low rpm but it is ok, the roller produces lot of air, so you don't need on demand high torque eg above 10k or 15k rpm.
 
#73 ·
Thanks for all the great info and an easy fix!

I finally did my 1998 SLK 230 -- no telling how long it wasn't working! I used this one from Jameco: QJT-360S-14280: Nichibo Taiwan : 12 Volt DC Motor - 4930 RPM : Electromechanical I put some really good grease on the bearings, so maybe it will last a bit longer than the old one. I plan on checking it before the warm weather every year from now on...

$3.49 USD + shipping is much better than the $170+ everyone wanted for the whole assembly, and it's a really good match to the OEM Bosch motor. I actually bought 2, plus two $0.49 motors (on sale -- higher nominal voltage, so they run slower at 12 VDC, but I thought they'd be worth a try) and some heat sink grease (for another project) because Jameco has a $10 USD minimum or they charge a fee. I went for the extra motors instead of paying the fee...

Thanks to all those who figured all of this out long ago and who made this fix really easy for me!
 
#74 ·
Hello everyone :smile

Has anyone by chance tried out what temperature reaches the ECU box when the fan is not working?
And, above all, what are the symptoms? Also random?
For example, supercharger working but sometimes ? Lost boost?
Bypass valve not working properly? A P0115 fault code from the coolant sensor could be expected or isn't related at all?


My ECU fan didn't work and unfortunately I don't know how long...
Initially, it only worked by tapping the black plastic in the middle, then I dismantled the piece (with a bit of difficulty)
I cleaned and lubricated and now it works, tested working with a good 12v battery, multimeter and so on... tomorrow I will mount it again.
Also, I tested fuses and many wires about voltage and continuity, and luckily nothing seems to be damaged ... but I wouldn't want anything to happen inside the ECU

In my opinion, this story is incredible, in reality ... mistakes can be made but not a so important fan with all that heat which does not imply a fault code with a temp sensor!!! :mad:
Unless the coolant sensor is working but it goes mad even because of that fan...and who knows? Not even some Mercedes workshops ...

Thank you
 
#76 ·
usually yes, anyway mine after deep cleaning and lubricant on the brushes starts and runs every time without hesitation...I directly tested many times with a 12v battery
maybe depends on the status but if it works for you, you need to keep attention anyhow...
when it works you hear it by leaning on the ECU black box, even if closed...


obviously the best thing is to change the motor
 
#78 ·
if in doubt, replace the motor. given the age of it its cheap insurance!
 
#85 ·
I recently replaced a dead ECU blower on my SLK320 and saw how air is drawn from the passenger compartment through a duct into the blower. My question is where is the air outlet? That ECU box looks pretty well sealed, and if the air can't get out, you're not going to have much flow. The engineers must've known that, but I'd like to check if the outlet is blocked or restricted somehow. All I can find is a tiny hole in the corner of the underside of the box.
 
#87 ·
yeah, it should, unless it's been removed. It's located next to the k-40 relay in the box. it might be hidden by some wires but you should be able to see it
 
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#92 ·
Hi Guys, I received my used ecu fan and it not working very well, I have to push start it, wondering if I can use a
"2004-2008 CHRYSLER CROSSFIRE ECU FUSE BOX BLOWER MOTOR COOLING FAN OEM"
It is still a Mercedes just newer than want I have and I know it's not a exact fit.
Please let me know your thoughts on it.

Thanks
 
#93 ·
Hi Guys, I received my used ecu fan and it not working very well, I have to push start it, wondering if I can use a
"2004-2008 CHRYSLER CROSSFIRE ECU FUSE BOX BLOWER MOTOR COOLING FAN OEM"
It is still a Mercedes just newer than want I have and I know it's not a exact fit.
Please let me know your thoughts on it.

Thanks
I purchased a used module fan out of a 2006 Crossfire. It was the same part number as the old fan on my 2001 SLK230 and it was an exact fit.

Old fan:
2698247


Crossfire fan:
2698248
 
#95 ·
I have a 1998 SLK 230 and in 2016 I replaced the fan motor with one from Jameco.com. The motor is still available from them for $3.49 ea - it's Jameco part number 206949 (motor manufacturer Nichibo Taiwan p/n QJT-360S-14280). It's now sourced as Jameco Reliapro as the manufacturer, so I guess Jameco wants other OEMs to be able to supply this motor, too. Amazon also now has it under the Nichibo Taiwan p/n - 2 for $6.98.

I'm an electronics engineer and I remember doing some research at the time - it was a close match to the MB OEM motor tech specs. It has a 4930 load RPM @ 12VDC, 350 mA. Jameco has a minimum order of $20 now (it used to be $10, with free shipping), or just tack it on to your next Amazon order. If you're reading this, good luck with your repairs!
 
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