BMW E46 Heater Fan Not Working Correctly

If you have a BMW E46, E39, X5, and I think the E36 with climate control and your heater fan has a mind of its own it is most likely the final stage resistor that is causing the problem.  In my case the fan stopped blowing, then after a day or two worked fine again for weeks, then stopped completely.  Other people report the fan changing speed for no reason.  The final stage resistor located just to the left of the clutch pedal on RHD cars.  It is located in an awkward location but it is possible for you to replace this with no special tools.