Blower malfunctioning I have a 2001 BMW 325 CI. Whenever I have the blower on for the heat, vent, or A/C, the blower goes from low to high and back seemingly at will. More often than not, it sticks on high. Also, whenever I turn the blower completely off before I turn the car off, the blower is always back on and stuck on high when I start the engine again. Is that normal? I would like to fix it, what part might I need? I ran codes on it, but it couldn't read whatever was going on. Blower motor? Thermostat? Something else? Thanks, Stina

Blower speeds in most cars (well, maybe not BMW) is set using a primitive resistive device with two (sometimes only one) end connections and 2 or 3 'taps' between them. The selector switch chooses either the input tap (high speed) or one of the other taps to introduce a fixed resistance in series with the fan motor.
Today, it would be a simple matter (and I don't doubt it is done) to create a very simple electronic circuit to replace the venerable resistor with much lower losses and little heat generation whereas the resistor does dissipate heat while 'wasting' the undesired voltage. 
I think that your car has an electronic control that is either failing or the switch that selects the speed has gone 'noisy' and is randomly selecting the speed on its own. Without having the car physically at hand to measure a few things, it would be hard to separate the culprit from the rest.