Assuming that the Keystone wiring color guide is correct, if that's a 12 ga wire, it's the awning feed circuit and if it's a 16 ga wire, it's the 7 way umbilical "backup lights" feed.
Does your awning work with that wire disconnected (check both the manual switch and the remote control activation)???
Also, with the In-Command system, check the "command center screen" as well as the remote.
If it's a 16 ga wire, Avalanche may have used that wire for the rear camera power ?????? So check the operation of the rear camera, if you have one.
Here's a link to the Keystone wiring color code:
https://keystone-rv-dealer-app.cdn.p...box_Oct20b.pdf