help with repairing blower motor regulator

[samheard]

HELP ANYONE- Need advice on how to replace the blower motor regulator on 97 e320.Fan speed only blows up to mid setting.Is this something i can tackle myself?-- am fairly mechanically inclined and have done quite a few repairs on car.Thanks for any responses. Sam

[shandy]

Check this thread; http://forums.mbworld.org/forums/showthread.php?t=121659&highlight=W210+blower+motor+regulator

Cheers,Geo.

[firstbenz]

Hello Sam,

I just replaced this myself. I even bought the car with this defect and learned from mercedesshop.com on how to change it. I used this to negotiate a lower price on the car and I got the part for $320 from Phil. My local dealer wanted $1100. Note that our year the regulator is not being built anymore and a dealer will replace the regulator, fan, fan housing, etc. Basically update it to the newer units in 1998+. I went with the unwired product featured here since it is an aftermarket regulator which does not require replacing all these parts and it does make the fan blow very hard on high. That is why I bought it, I live in Arizona which hits about 115 in the summer. You can also get a new one from silverstar recycling in Rancho Cordova CA for $250. They claim it is our year and brand new.

Anyways with a screwdriver and I believe it was a torx head and about 30 minutes you can get this done. Located under the dash on the passenger side. Might as well replace your cabin filters also. I found out this is behind the glovebox, glovebox comes out with 4 or 6 phillps screws. The glovebox comes out and a small door holds the two cabin filters which can slow down air recirulation if dirty. They are bright white brand new. I had leaves in my old ones!!!

Hope my experience helps.

Floyd

[JimF]

Originally Posted by samheard

HELP ANYONE- Need advice on how to replace the blower motor regulator on 97 e320.Fan speed only blows up to mid setting.Is this something i can tackle myself?-- am fairly mechanically inclined and have done quite a few repairs on car.Thanks for any responses. Sam

If you really want to repair your present blower regulator, check out this thread. You see an schematic of what parts are inside of the b/r and how it works. The final schematic is Post#30.
Bad blower motor regulator wanted

[Matt L]

Originally Posted by JimF

If you really want to repair your present blower regulator, check out this thread. You see an schematic of what parts are inside of the b/r and how it works. The final schematic is Post#30.
Bad blower motor regulator wanted

That's a nice analysis. I assumed that it was a power bipolar transistor for the output stage, but didn't assume that it was so simple. Those things are too pricy for what's inside.

Unwired's product appears to be a switching circuit; they claim no need for a heat sink. That would be preferable, but much harder to design.

[JimF]

As you probably know, simplicity means 'longevity'. . . supposedly. The power transistor must dissipate the unused power; worst point as appx at the middle of the setting.

Since there's a lot of power dissipated, a heat sink is mandatory. When mine failed, I didn't find any silicon grease on the bottom of the b/r.

As can see repackaging the existing part into the same outline (or similiar) is the hardest problem but if you're good at that sort of thing, you can repair it sucessfully.