Microswitch, auxiliary water pump — a genuine BMW part, number 64 11 8 373 984. The number stamped on the part is 64118373984; BMW's catalog files it under the short number 8373984. You will find it on our AC & Climate Control shelf, under Other Heater and Air Conditioning parts. It supersedes the older number 8372798, so a part carrying that number is the same part.
It fits the E46 sedan, coupe, touring and compact (320i, 323i and 328i, 1999–2005), with the M52 engine — and the European-market versions.
BMW draws it on 2 diagrams, among them Electric Parts for Heater (64_0815) and Electric Parts for Heater (64_0991). It weighs about 7 g (under 0.1 lb).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.
