No Max AC, no Vacuum?

[GTJon]

Hello all. New user here. I have a 2001 Explorer XLT V6. Love the truck. It has about 140,000 miles. It is stock. I bought it about a year ago to do driver training with my kids.

Anyway, the AC works great, but last week the MAX AC setting quit working. I search the internet to see about possible issues. I first looked to see if the little arm was broken that controls the door. It is OK.

I then pulled the vacuum line off the actuator for the door. Using my gauge I saw there was zero vacuum. I looked in the engine bay and found a broken grey vacuum line. I blew through the line going into the firewall and it is the one going to the actuator. I thought "AH HA, this must be the issue".

I started the motor and measured the vacuum at the broken line going toward the front of the engine which I assume was the vacuum source. Zero. No vacuum.

So, I see this grey vacuum line going into a device located near the front passenger side of the engine. I am unsure what this device is but by doing some searching it looks like it might be a heater control valve???

My question to the forum is this: Could a bad heater control valve cause the vacuum to fail at the MAX AC setting? IF NOT, then I need help to trace where the MAX AC gets its vacuum supply.

Thanks!
JON

 

[SoHK_alumni]

Vacuum line starts at the intake manifold and goes to a black softball shaped/sized vacuum reservoir under the air cleaner.

There's a one-way vacuum check valve built into the ball.

From the ball, the vacuum line goes rearward and clips to the bottom of the air box under the fan motor.

Inside the truck, the vacuum line resumes it's journy to the heat and ac control panel.

From the control panel, the vacuum is routed to the heater valve and max a/c vacuum solenoid.

A failure of the vacuum can occur and any of the joints or connections easily, in one of the lines on occasion and on rare occasion, at the selector switch itself.

 

[swshawaii]

^ http://www.explorerforum.com/forums...n-right-front-wheel-well.303406/#post-2623161

 

[GTJon]

^ http://www.explorerforum.com/forums...n-right-front-wheel-well.303406/#post-2623161

Thanks for the link. I was just getting ready to type "I don't see any ball or globe" when I spotted your reply. I guess I need to take the fender liner out as I took off the air box and the globe appears to be deeper yet.

Thx!
JON

 

[GTJon]

Vacuum line starts at the intake manifold and goes to a black softball shaped/sized vacuum reservoir under the air cleaner.

There's a one-way vacuum check valve built into the ball.

From the ball, the vacuum line goes rearward and clips to the bottom of the air box under the fan motor.

Inside the truck, the vacuum line resumes it's journy to the heat and ac control panel.

From the control panel, the vacuum is routed to the heater valve and max a/c vacuum solenoid.

A failure of the vacuum can occur and any of the joints or connections easily, in one of the lines on occasion and on rare occasion, at the selector switch itself.

Yep. I think I am looking in the wrong direction. As you might see in the third post here, I could not find a ball/globe under the hood anywhere. Sees it is buried in the passenger fender well according to some posts?

I will keep digging.
Thx.
JON

 

[GTJon]

Untitled by Jon Stepro, on Flickr

Update. I got behind the glove box and found the white block where I assume the vacuum supply comes into the cabin. I poked around with my gauge and found there is vacuum here. Third opening down on the right. See photo.