My A/C works in the back but not in the front vents on 2006 Ford Expedition

I check the fuses but they look good not sure where to go next

1 answer 4 comments
Is it not blowing ?
Yes it is blowing just not cold air
Has the freon been checked
Nope I thought it should be ok if the back A/C was working how would I check it

With a gauge set as any a/c system.