help with repairing blower motor regulator - PeachParts Mercedes-Benz Forum

JimF · #1 11-11-2006, 11:07 AM

Quote:

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.
http://www.peachparts.com/shopforum/showthread.php?t=76998

Matt L · #2 11-11-2006, 11:23 AM

Quote:

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.
http://www.peachparts.com/shopforum/showthread.php?t=76998

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 · #3 11-11-2006, 11:49 AM

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.