I haven't looked at all models but on my 2011 GDI, however from what I can see on KGIS (SI - ETM) the 20amp Audio fuse looks after a lot more as others have stated:
That being:
Audio
BCM
A/C Control (either auto or manual shift)
Instrument Cluster
TP Monitoring
Ign Key Illum & Door Warning Switch
Electro-chromic Mirror
Passenger Vanity
Driver Vanity
Room Lamp
Overhead (Map) Lamp
Luggage Lamp
It also looks like it is the main power (B+) feed for the IPS System, that means it may control the IPS modules that look after to following:
Note: Some of these could be duplicates or secondary power lines to some of these system:
Fog lamps (IPS 6)
Head lamps (IPS 4, 5, & 7)
Rear Combo (IPS 7 & 10)
Licence Plate Lamp (IPS 7)
Power Windows (IPS 3)
DRLs (IPS 8 & 9)
UVO or Navi Audio (IPS 10)
Electro-chromic Mirror (IPS 10 as well as the fuse wire above)
Seat Warmer (IPS 3)
Auto shift illum (IPS 3)
AC Control module (IPS 3)
Multifunction switch (IPS 3)
Instrument Cluster (IPS 3)
Multi Switch ? (IPS 3)
Hazard switch (IPS 3)
Aux & USB Jack (IPS 3)
Glove Box (IPS 3)
Telltale & SBR ? Lamp (IPS 3)
Driver CCS ? Switch (IPS 3)
Not bad for a little 20amp Audio Fuse. BTW the RF Ant Fuse appears to look after just the RF Module in the antenna - how boring :nerd: