1999 Mercury Mountaineer AWD 5.0

[Colinius]

Hello everyone. My issues appears to be simple but sadly I am having immense difficulty locating the other half of a vacuum line. My heater control valve, which is in the heater core line against the firewall, has a gray vacuum line attached. This line is broken about 18” away from the valve and for the life of me, I can not find the other end to repair it. Any ideas would be wonderful.. thank you in advance.

 

[koda2000]

There is a round vacuum ball/reservoir located in the front of the passenger side inner fender. One line goes to engine, which supplies the vacuum, the other feeds various things like the heater control valve, it also feeds into the cabin and then to the HVAC controls.

If you drop the plastic inner fender (you can even remove it by taking out a few screws and some bolts) you'll get a very good view of the ball and the various lines connected to it. Then you should be able to determine where the broken line went.

An easy way to repair a broken line is with a short, tight fitting piece of rubber vacuum line of the appro size as a splice, or you can buy a package of new plastic vacuum line at any auto parts store and replace the broken line. It wont have the special ends though.

 

[Craigerz]

I can take a picture when I get home but I'm pretty sure it runs back into the fire wall under the blower fan. You can pull off the glove box and see where all of the vacuum lines that control the EATC run through. That's where I would check first.

 

[Craigerz]

I have my inner fender down at the moment is why I can take a picture

There is a round vacuum ball/reservoir located in the front of the passenger side inner fender. One line goes to engine, which supplies the vacuum, the other feeds various things like the heater control valve, it also feeds into the cabin and then to the HVAC controls.

If you drop the plastic inner fender (you can even remove it by taking out a few screws and some bolts) you'll get a very good view of the ball and the various lines connected to it. Then you should be able to determine where the broken line went.

 

[Colinius]

Thanks fellas. I’m walking out there now to see what I can find out. I’ll keep you informed.

 

[Turdle]

There are a few good pics in my diagnostic thread linked below. Hope this helps

How to: - 2nd Gen NO AC ( or heat) FROM VENTS!!! A "How to" what to look for thread

Looks to me the "break" is right in the inner fender area. Could have been melted by the exhaust manifold. Make a clean cut to be sure there is no blockage from the melt, and rejoin with some small rubber line used as a splice.

 

[Craigerz]

Here is where it goes in under the fan motor