flakey w210 heater fan control - PeachParts Mercedes-Benz Forum

landev · #1 12-19-2007, 12:16 PM

Well, now that it's quite chilly here in northern Idaho, my control for heat in my '96 e300d seems to be on the fritz. Seems that when the car is started in the morning, no setting will get the fan running until the car has run for about 20-30 minutes. I can feel heat in the vents, but there is no force pushing it out. Suddenly, about 1/2 way to work, the fan kicks on and there is some decent (but not overly hot) air circulated into the cabin. Is this a flakey sensor causing this problem (the CC fan up by the mirror has always been noisy) or is it more likely something to do with the fan control (or both)? Shouldn't the fan control kick on the fan when in manual mode, regardless of the temperature?

'pretty clueless on this one....

Thanks in advance!

-l-

Matt L · #2 12-19-2007, 12:25 PM

Using the manual control for the fan will eliminate sensor problems. If it doesn't work properly on manual, the fault would have to lie in the N22 pushbutton control module, the wiring or the blower regulator. It's more likely to be the regulator.

landev · #3 12-19-2007, 04:10 PM

Initially, that diagnosis didn't sound too bad, but as I have looked around a bit at the fix, I'm doing some cold sweating. I found the link to a fix using a regulator out of a W140 (http://mbworld.org/forums/showthread.php?t=153918) that didn't look too bad, but I have also seen posts stating that a new blower motor assembly is the only fix. Does anyone know if the fix using the W140 part works and, if so, what part number I am looking for?

Thanks,

-l-

Matt L · #4 12-19-2007, 04:24 PM

First ensure that your blower motor itself is working properly. If you unplug the regulator from the motor and ground the (newly-unplugged) motor lead, the fan should run at full blast. Actually greater than full blast.

If your motor is questionable and the regulator is bad, you should get the set. I have read that the 140 regulator (which needs modification to the connectors) does work, but I have not done it to my car and do not know the part number. Also see the sticky about the "UnwiredTools product announcement" in this forum for another repair path. I also have not used this part.

You might find more information by searching the W210 forum at BW. That way, you are less likely to find posts of putting a 140 regulator in a 140.

landev · #5 12-19-2007, 05:07 PM

Matt,

Thanks for the info. I did find a behr part number for the 140 regulator (1408218451). I wasn't aware of the UnwiredTools option, but for the $120 price difference, I would prefer to wire in the 140 regulator. I have found a few more posts on other site of people loving this fix... just a bit nervous about a $217 fix that doesn't last. I will give the motor test a shot and see what happens... for all I've been able to sift through, it sure sounds like the regulator.

Thank you!

-l-

landev · #6 12-28-2007, 08:25 PM

O.K....
I received the new blower motor regulator and did the swap out with the original part. It works like a dream! Seems that what I thought was to be the German part replacement, had a big sticker on the bag saying "made in France"! It was, though, the Behr part number and not the less expensive part that was advertised. As my blower motor was pretty much T.U., I did the replacement regardless of the country of origin of the part. What I did notice, though, which causes me some concern is that there was much brush dust scattered around from the motor. Does anyone know if there are brushes available for the original motor? I would like to put some new brushes in if they can be had.

Thanks All,

-l-