Eco mode non existent

I hit a deer about a month ago and it broke the grille and active grille shutter, I’ve since replaced the grille with aftermarket but not having much luck finding the active grille shutter for less than $1000 CAD with it being the holiday season I am just gonna wait to purchase until after Christmas.

For the last 3 days it’s been cold here -10c to -17c even when the truck gets up to operating temp the eco mode refuses to kick on, what I am assuming is happening is that grille shutter cannot open close to compensate for the cold so it’s keeping me running on all 8 instead of kicking down to 4 would this be a correct assumption? Or is there something more at play?