what is this?

[RachHandinit]

This never stops running and pumping..? what is this?

[jesilvas]

Vacuum pump which operates your blend door for the HVAC system and 4wd hubs if you have them
You have a leak somewhere.

[RachHandinit]

is this under warranty? what is the blend door for the HVAC system

[bentstroke_02]

Mine runs to i went to the ford dealership they said it wont hurt nothing running. It is very annoying tho that is for sure lol

[jesilvas]

Unless a 6.4 is different in the vacuum system from a 7.3, that dealer is dumb and just didn't wanna do the work.
The blend door changes between floor, defrost, and vent.

[Clayton1985]

Originally Posted by jesilvas

Unless a 6.4 is different in the vacuum system from a 7.3, that dealer is dumb and just didn't wanna do the work.
The blend door changes between floor, defrost, and vent.

I believe 6.4 is as I broke a vacuum line when I did my egr delete and the pump ran continuously. I unplugged the elec connector so I just have to manually lock my hubs in for 4x4. My HVAC selection works fine.
So as far as I can tell its good for the ESOF and thats it...
I remember our 6.0 work trucks the pump would fail once in a while and heater would be stuck on defrost (default)

[RachHandinit]

All of a sudden this thing is starting to make weird noises and sounds like it is struggling and getting stuck. Is this bad and I still dont understand what exactly this thing does.

[SuperCrutyPS]

Originally Posted by RachHandinit

is this under warranty? what is the blend door for the HVAC system

You could probably call the dealer and ask - If it is, have them deal with it. Just my opinion.

[Shockwave]

I wondered what it was too, and why Ford mounted it on top of the fuse box?
When I had to swap out a fuse, the plastic line broke. A real PITA to replace.

[Refugio]

Like others have said.... It is your vacuum pump and it is for the Auto Locking hubs when you switch the ESOF to 4x4.
It should not run constantly. Only long enough to build up vacuum in your canister reservoir. If it does not shut off after about a minute then something is leaking.