GM stands for General Module. It is a black box, in generic terms, providing control functions for vehicle systems

IKE stands for Instrument Cluster, but I don't know if it means the cluster itself, or a control module in the cluster. Presumably the word for cluster starts with a K in German.

The important thing is that none of these have switches for your mirror heating that you can control manually, the heating is automatic based on exterior ambient temperature as advised by the instrument cluster to the general module, which talks to the door modules.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue