I have been experiencing 'electrical burning smells' for a couple of years on any HVAC fan speed except full speed, so I finally decided it was the blower resistor - part no. 64 11 1 468 524 for my car. The Bentley manual wiring diagram says the blower resistor is located on the 'left side of the right foot well'. Wrong - it is located on the 'right side of the left foot well'. Getting the old one out and the new one in was a pain. You can barely see it from deep inside the left foot well - the resistor has a blue plastic case - the blue color will help you see it amid all the other stuff in the area. There are two plastic tabs - one on each side of the resistor that you need to squeeze to remove the it and a 4-wire plug that you need to remove from the resistor. You will need to remove the 'Trim Panel Foot Control' panel - part no. 51 45 1 978 935 to get close to the resistor. This panel is some sort of plastic and cracks very easily. This panel has a HVAC duct mounted on top of it and supplies air to the driver's side foot well and is a $131 piece that I will do without - I will try to repair my broken panel. After replacing the resistor, the smell is no longer present. This resistor mounts within the HVAC system air stream - the air flow evidently keeps the resistors cool, but it collects dust and crud over the years so I guess this accumulation of stuff contributes to the burning smell. Every time I repair something, a piece of plastic crap crumbles - hate plastic crap.

Tom
95 540i