I am in need of some help I have on a 1997 v6 4.0 w/air 4wd. my problem is there are to vacuum hoses on the round vacuum tank one comes from the engine vacuum port the other one is broken off and I have looked but cant fine where it goes???? If you can help me please let me know. Thanks George

 

That is called the Vacuum reservoir, the round ball

It is connected to intake manifold, to get Vacuum
And then connected to the Firewall and Vent controls for cab

In the engine bay passenger side firewall you should see a Black and a Gray vacuum hose, coming out, they are hard plastic lines so may look like wires
Gray vacuum hose will go to the heater hose valve

Black hose goes to the Vacuum reservoir, it often get damaged by heat from exhaust manifold.
You can repair or replace this hose with regular rubber vacuum hose, hard plastic is just cheaper which is why automakers use it


The vent doors in the cab are operated by vacuum, Defrost is the default(no vacuum) position.
So with no vacuum and fan on all the air should be coming out of Defrost vents
This doesn't effect AC just no panel or floor air

Vacuum reservoir is needed because engine vacuum changes with throttle position, it drops close to 0 when accelerating.
So without the "stored vacuum"(reservoir) every time you accelerated the vent doors in the cab would shift to Defrost vents.
And this happens when vacuum reservoir has a leak

 

Ron thank you for your reply. I have looked before I see the gray line but do not see the black one I will look tonight again and see if I can find it. I will let you know how I made out. Thanks George

 

It is there, should go into firewall next to Gray hose

 

Ron thanks found it behind glove box. replace line to the vacuum tank all looks good now. Thanks Again for your help. George

 

Good work

Thank for posting the update and fix