If this is like the 97 era W210 / W202 / R129 , that isn't a resistor for the blower, it is an electronic speed controller. ( sort of like a dimmer for a house light )

Before changing you need to monitor control voltage ( with a meter and looking at on board data ) and see if it is falling off. If it is, there is a problem with the in dash HVAC control. There are ways to pull data and codes from the HVAC by pushing buttons on 97 era cars, not sure about 01.