I don't know what will happen if you swap in a used (uncoded, un-synched) DME and turn to position 2..

Is your new fan installed?

If not, do you have anyone local with a BMW to test your fan for you?
Most of the E46, E39, X3 of the same vintage use the same connector and a similar fan

You can use INPA, but it should also turn on if the temp sensor is disconnected.

I recently got the wiring (male/female connectors) from the junkyard and an old aux fan to make a 6 foot pigtail that would allow me to park another BMW close to mine, nose to nose, plug in a suspected bad fan- still installed - to a BMW with a working Aux fan and test it.