One of the fan sensors is in the passenger side of the radiator. Pull the plug off the sensor and put a paperclip in the bottom hole and one of the top holes of the plug. This will be either the slow or fast fan speed. Putting the paperclip in the bottom and the other top hole will be the other fan speed. This is the most reliable way to check if the fan is operable at both speeds. __________________ SOLD!!! 1999 332ti //M Sport Titanium Silver M3 S52 3.2 I-6 Engine, M3 Clutch w/ ti Getrag Trans, Z3 3.15 LSD medium case diff and half shafts, OEM Hatch Spoiler, Eurosport HP Underdrive Pulleys, FDM, 17" DS1 rims, M3 Front Struts & Springs, M3 Instrument Cluster, 3-spoke //M steering wheel with tri-color stitching, SSK, CCFL Angels in Depo projectors with 5k HIDs |