Blower motor failure or resistor problem? 1994 bmw 540i

[ludur]

Hello guys, so, last week my a/c and all the air equipment was working just fine!
A couple of days ago, I started the vent switch, and nothing, no air coming out of the vents in any position, just a little buzing from the blower (I guess), but no air at all out of the vents.
I am trying to figure it out if I need an entire new blower motor or if is the resistor (final stage unit as bmw calls it) that is damaged.
Any way to know what it is? Is it a good idea to change the resistor as well, in case I need to change the blower motor?
Any part number that could help me find what I need. Las 7 of my vin are: GF25612
Thanks!

[moroza]

The resistor is bypassed on speed 4. If the blower doesn't work on that speed, either it's damaged or there's a wiring problem. A buzzing noise suggests the motor is spinning but the impellers (hamster wheels) are broken.

No need to change the resistor if it's not broken, but replacing the cabin filter is a good idea, as is clearing out debris while you're in there.

Blower motors seem to be the leading cause of E34 fires. Don't cheap out on this part. I don't know what's available these days but four years ago I got a Behr (made in Austria IIRC) for ~$140. VDO turned out to be made in China. Part numbers are 64118390935 or 64111374377.

Carry a fire extinguisher in all cars regardless of age or type.

[Sir Montalbon]

I second everything moroza said, with one addition...

If the buzz if more an electrical buzz/humm, it may be a seized motor. Sending power to a seized motor is not in anyone's best interest as it will produce heat and could possibly start a fire.

If the buzz is more mechanical, like the hamster wheels have broken and the shaft is spinning and contacting them, then not as dire as a seized motor, but still not good.

Regardless, I would leave the air off until you can get in there and take a look.

[ludur]

Thanks for the replies guys, well, it is not an electrical buzz, it sounds like the motor is spinning but really, really slow, so you won't feel any air coming out of the vents. I'll definitely get a new blower, a good one, and also I'll change the current fuse that is a 30A to a 20A, as I read somewhere, that this is the cause for fire that you guys talk about.
Once again, thank you!

[moroza]

A seized motor, especially with an (almost?) undersized fuse, would blow same or start a fire within seconds. I doubt it's seized.