Ok so my blower motor stopped working. I took the motor out and tested it and it works, I testedthe two relays next to it and they work. I purchased a new control unit( dash buttons) and that didn't fix it. Finally I found this part that looks like it had resistors in it. So here are my questions:
1) what is this?
2) will it cause my blower to not work?
3) what size resistors can I solder back in it?
4) what does the inner schematic look?
[IMG]http://img.photobucket.com/albums/v674/phidelt583/i
mage-1.jpg[/IMG]

 

Another pic with the cover on, it is located below glove box right next to the center console

 

That's the fan speed control. Search the Denso part #.

 

BMW calls it a final stage resistor and yeah its for the blower motor to create resistance when fan is not on high...OEM ones on BMWs are poorly designed and failure is common...good to know i have another one of the damn things. :-P

 

All resistors are color coded. You can type in the color of the bands and get the ohm rating. Then plug in your vom meter and check to see if it is reading right. You can always just swap it out, or try a wide range variable resistor that lets you dial it in. (Radio shack dorks will love you for asking).

 

the BMW ones have transistors in them and I could not find a way of testing with just a multi-meter..as much as I hate guessing and buying a new part to fix a problem that is what I had to do..luckily it worked