Hi from across the Tasman.
You don't have to have climate control to have the air pump. It is in all models. It sucks cabin air past the sensor in the light switch panel in the roof and the sensor measures the temp and compares it to the settings on heater dials and the heater and A/C adjust output to maintain even temps in the cabin. I have heard that you can place a small piece of tissue paper to the small grill in the roof light switch to test the suction of the pump, but its just as easy to listen to the hum from the glove box.

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1993 320E 140,000km