Resurrecting this old thread to help anyone that may be still experiencing this.

There is a service bulletin out for this issue, covered under warranty. Here is the pertinent info:

SI B 62 10 06 Instruments
February 2007
Technical Service

SUBJECT
Instrument Cluster Back Lighting Fails Sporadically
MODEL
E46 (3 Series)
E83 (X3)
E85 (Z4)
Vehicles produced from August 31, 2003 to July 27, 2006.
SITUATION
The customer may experience brief failure of the instrument cluster back lighting, air condition control or radio. The failure will last between 10-15 seconds.
CAUSE
Light Switching Center (LSZ)
CORRECTION
Replace the LSZ with updated parts as listed below. Please compare with EPC before carrying out the replacement.

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2014 Mazda 3 GT: Ø Consumption: (click for details)