Do your heated seats work? Looks like heated seat relays are powered by the same wire from the BCM.
I couldn't find how the wire is routed, just a view of the BCM.
I did come across an interesting passage in the Rear Window Defogger Description text: "If battery voltage is low, the BCM will disable the rear window defogger by removing the battery positive voltage supplied to the REAR DEFOG relay coil."
How's your battery voltage?