Fan controller issue

[Zakattack7.3]

I've been having this issue for a while now and I've decided it's about time to figure out what's wrong. That control switch that adjusts where the fan blows out heat/cold air (towards your feet, defrost, etc) seems to not work. The fan speed control works fine but all of the air seems to be coming from the front of the dash as if it's set on defrost and no matter where I turn the dial, it still comes out there. Any suggestions on what could be wrong?

[tonyf250]

You have a vacuum leak. I have the same problem from time to time. Check to see if your recirculate works as well. I would be willing to bet that it does not work either.

[ttyR2]

Classic sign of a vac leak, usually related to the hoses that run the front locking hubs.

[Zakattack7.3]

Yeah I've read a few places that the majority of vacuum leaks on these are caused by the hoses running to the front locking hubs like you said. I'm new to the auto locking hubs (the ones on my old truck were manual). So is this the hose I should be looking at on either side of the truck?