Not sure if this is important or not, seems like a vacuum hose, it just crumbled away so I don't know where it even went to. You can see it there, I put a piece of masking tape on it. It looks like it goes through the firewall, but idk where after that. Anybody know where it goes? Or what its for? Important or not? Easy to replace?

 

The little white vacuum hose connects to the little vacuum actuator above the blower motor and controls the max air / recirculate function of the a/c. Hose only gets vacuum when max air is selected.

 

New to these style trucks, can you maybe get a pic for me of where it connects? And does that mean that the other side connects to the back of the AC selector in the cab?

 

It sure does. Right back to the max a/c - defrost control. I'll try to get you a picture tomorrow.

 

Just replaced a 5 inch section of this same line, Napa has hard tubing for this repair with the rubber connectors, I guess I got lucky mine was only bad in the same area as your picture shows.

 

Ok I just pulled the AC unit out and the line is good there, so I pulled it out of the conduit and it seems to be good there too. I guess I'll hit up the napa today and get some more, but I still have no clue where it is it goes to, so much crap under the hood on these 300s I don't know what's what