Fan stuck on high

[Saphiro]

My fan/climate control switch only seems to have two settings, suddenly. High (4) or slightly slower, it's always on. Did the switch go bad? Could it be that the fan is wearing out? Have any of you guys had this problem before?
Phil
1990 525i

[BavarianFanatic]

It's the "sword" also known as the final stage unit. It's a bunch of resistors used to vary the fan speed. A quick search should yield dozens of results with more details.

[E34Mekanik]

Oh yeah that's your "blower resistor" as it's called in the newer BMWs. It's triangular and fist sized in E36s, E39s, E46s, etc. (E38 being a whole 'nother story)
In E34s it's a long 'sword' board circuit resistor looking thing as CG53 said.
You can get to it under the dash from inside the car but you might have to loosen a few things under the hood first. At least that's how the M5 is.
Searching E34 blower resistor might help.

[Saphiro]

Thank you all. I'll check that out.
I got in the car today and hit the starter, I instantly smelled burning electronics and then a whole bunch of white smoke poured out of the vents. Of course, I immediately shut the car off thinking that it was a fire. Once I determined that everything seemed 'ok,' I turned the ignition on and more smoke came out, but only for a second or two. Now, the fan switch works better than it ever has and I can use all of the speeds. Any ideas as to what that might have been? Is it a common symptom of the blower resistor going bad?

[E34Mekanik]

Poltergeist?
I don't know what to make of that. White smelly smoke is not usually the first sign of a problem fixing itself, but if you say so...
Over time, the blower resistor loses its ability to resist electrical current, and starts to absord more and more heat, cooking itself to death. Which sounds like what just happened. But now your fan speeds function normally...
I just don't know, sorry.

[Saphiro]

I think that I'll just go ahead and replace the resistor. Probably the safe route, I guess.