What controls auxlilary cooling fan activation on a '97 E 420 (210.072)... relay? cycle module? control unit?

The control module found behind the headlights (027 545 80 32) on other models is not present on this vehicle.

Is there a cycle module (perhaps N65) that is responsible for activating the fans? If so, is this module located in the electronics bay near the front windshield?

Or is fan activation integral with the MSG (ME 1) control unit?

The fans are functional when provided external power but fail to run when the A/C compressor is activated or engine coolant temperature is elevated.