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Ask Chris (aka- Moose) Your Own Question
Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 47946
Experience:  16 years experience
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2001 ford excursion: air not blowing through the vents on the dash

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air not blowing through the vents on the dash. I can hear the fan blowing but the air does not come through the vents in the dash. 2001 ford excursion

Hello Pjeanl,

Thanks for coming to Just Answer to ask a question.


Is all of the air blowing out the defrost?

Which engine?

Customer: replied 8 years ago.
2000 Excursion with a 7.3 diesel. The air is blowing out the defroster but is not coming out the vents on the dash.
I need you to open the hood and turn the key to the run position and look directly above the front passenger tire at the vacuum reservoir and see if the vacuum pump there is running. This pump provides vacuum which is used in the dash to control the mode doors. No vacuum means the dash will default to the defrost only. This is your first check. If its not running then check for power and ground to the pump. If there there then install a new pump. If it is running then see if its building up vacuum and storing it and check for hose leaks under the hood and look and listen around and under the dash.
Customer: replied 8 years ago.
We found the vacuum, and it seems that it is running. There are two plastic tubes coming out of hte vacuum, looking from the front of hte engine, the one on the left has two lines connected to it and the one right has a line connected on the side of the tube, but nothing connected to the end of the tube. If we put our finger over the end of the one that doesn't have anything connected to it, it makes a different noise.
Sounds like your missing a hose or a plug there. Look around for a misplaced hose there. The different noise is the pump trying to build up the vacuum because with the leak it is just running freely.
Customer: replied 8 years ago.
We went out and plugged the opening of the tube for about 2 minutes, but nothing happened. We noticed that the tubes attached to either side of the vacuum are attached back to the vacuum at the back side. We do not see any tubes leading from the vacuum to anywhere else. There is also a line attached to box that my husband says is the vacuum resevoir (according to the part number we looked up.) The tube that we held our finger over is flared at the end. Any ideas?

Look at these below


Customer: replied 8 years ago.
We followed the line from the reservoir to the inside of the cab. It seems like everything is connected, and we can't hear any leaks, but the vacuum runs constantly and does not shut off. Do you think it is the vacuum that is bad or the reservoir that has a leak?
Something has to be leaking for the pump to continually running. I would hate to send you into the dash tearing it aprat in search of a leak or a faulty defost mode door if in fact the concern is outside the vehicle under the hood. I suggest you purchase a vacuum pump from your local parts store and use in place of the electrical pump and see if you can get vacuum to produce and hold in the reservoir. DO NOT SUPPLY AIR TO THE RESERVOIR TO FIND A LEAK. It will blow the reservoir up immediatly. If you still cant find a issue please reply back and we will start o nthe dash. A vacuum pump should reach its max capacity in about 10 seconds and the pump should shut off. If you have 4x4 then check those supply hoses as well for leaks and or cap them off so the only supply is to the dash and or cap them all off and see if the tank can hold vacuum on its on with no outlets connectected and capped off.
Chris (aka- Moose) and 4 other Ford Specialists are ready to help you
Customer: replied 8 years ago.
We will try what you say and get back to you for more information.
That will be perfect, You can still reply right here if needed and I will reply back anytime I am online
Customer: replied 8 years ago.
We just took it for a drive and the 4 wheel drives seems to engage. So does that mean that the pump is working because it also controls theXXXXXswitch?

How did you verify the front hubs locked in

Customer: replied 8 years ago.
We drove and when we switched toXXXXXyou could feel the lunge and click like it went intoXXXXX
Did you make a tight turn and verify the hubs locked in and caused steering bind up when driven slow?
Customer: replied 8 years ago.
When we switch to highXXXXXI don't feel much difference, but when I switch to lowXXXXXI can feel the binding when I turn.
Ok there should be binding while turning in 4 high as well so I am not 100% your hubs are locking in (vacuum controlled). So now you need to do the steps indicated prior and disconect all lines from the reservoir and plug off the holes and see if the pump runs and then shuts off once vacuum is built up.
Customer: replied 8 years ago.
I took off the lines and plugged the vacuum pump all the holes. Turned on the ignition and let it run for about 1 minute. The vacuum pump still runs. So I will go purchase a new vacuum pump and see if that works. Does that sound right.
This has concluded its either a pump not makeing vacuum or a leaking reseervoir this is where the hand vacuum pump I requested you get earlier comes in handy.
Customer: replied 8 years ago.
Just had my neighbor come home and I guess I tested it wrong. I disconnected all the hose lines and plugged everything up. My neighbor said I should have pulled off the line to the reservoir and when I did this and plugged the hole the vacuum pump shut off. So does that mean I have a leak in a line or the reservoir. If it's in the line how do I test for that.
Since the pump did shut off and the reservoir held vauum this means you have a line leak and you must feel for the leak by hand or just replace the lines.
Customer: replied 8 years ago.
Okay, How many lines go into and come out of the reservoir? I took the other side next to the line coming from the pump off and put my finger over the hole in the reservoir and it seems to be sucking , but the pump does not shut off. I held my finger there about a minute, but it continued to run. Does that mean the reservoir is bad, or are there more than one line that attaches to the reservoir?
You have already declared the reservoir and pump are good since your neighbor helped you and it shut off and held vaccum. There is only 2 lines. One to the 4x4 hubs and one to the dash.
Customer: replied 8 years ago.

when our neighbor came over we only tested the pump, as we disconnected the line from the pump and put our finger over the line before it went to the reservoir. My nest test was to remove the line that goes out of the reservoir to the lines that go toward the dash and some where under the engine. I held my finger over the side of the line that comes out of the reservoir which should make the reservoir air tight, but it did not shut the pump off. My question is is this a reliable way to check if it is the reservoir or the line that is leaking. Do you need additional payment inorder to help us get this completed. We appreciate your patience with novices.
The test was sufficient enough. If the reservoir will not hold vacuum then its bad.