The blower motor for the heating right?
Here is how to find the resistor:
Remove the knee bolster.
Look up and to the right of the gas pedal, behind the obc.
Locate a white or green trapezoid plastic looking thing.
Unplug the 4 prong plug.
Pull it out. You might need a flat head screwdriver to assist with any clips.
Here is a DIY on replacing the blower motor of it goes bad: Doug's Domain :: BMW E36 HVAC Blower Motor DIY
This link contains pictures as well as excellent trouble shooting. Any questions feel free to ask.