2001 Ford F-150 Vacuum Leak?

Tiny
JERRYAUSTIN
  • 2001 FORD F-150

Heater problem
2001 Ford F150 V8 Four Wheel Drive Automatic 185000 miles

My F-150 is not putting out the heat that it used to. Heat level is equivilant to having the knob at the 11 o'clock position when in full hot. I also have a problem with the distribution door switching to defrost from floor when I'm going up a hill. All this started at the same time. Any suggestions?

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Wednesday, February 10th, 2010 AT 9:11 AM

33 Replies

Tiny
RACEFAN966
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It sounds like a heater blend door actuator problem. If you have a digital multi meter we can do some testing and make sure. Let me know what you want to do.

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Wednesday, February 10th, 2010 AT 10:01 AM
Tiny
JERRYAUSTIN
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I do have a digital Multimeter. Be happy to troubleshoot with it. Please let me know what to do.

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Thursday, February 11th, 2010 AT 5:08 PM
Tiny
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We don't need the meter yet but will. First I need you to bring the truck to normal operating temp. Now Turn blower motor switch to low position. Turn selector switch to panel position (Max A/C position if you have A/C. Turn temp knob to full cool and check for cool air. Now turn temp knob to full warm check for warm air. Now rotate temp knob from full warm to full cold. If the temp don't change then I would like you to check fuse number 5 (15amp) in the in truck fuse box. Let me know what you find here and we will go from there.

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Friday, February 12th, 2010 AT 10:29 AM
Tiny
JERRYAUSTIN
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Everything so far works as advertised. Except the temperature of the air. When adjusting temp control from Hot back to cool, results were immediate all the way thru the range of the knob. Just that it starts out cooler.

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Saturday, February 13th, 2010 AT 3:49 PM
Tiny
RACEFAN966
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If you would use the pic below to check the vacuum lines and make sure there are no crack in the rubber hoses as well as the plastic ones. If there are cracks in the plastic ones I would get rubber hose that will go over it, using it as a splice. Let me know what you find ok.


http://www.2carpros.com/forum/automotive_pictures/249564_Graphic_200.jpg

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Monday, February 15th, 2010 AT 10:47 AM
Tiny
JERRYAUSTIN
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Wish I could use the pic. Diagram itself is clear, but when I blow it up to make it legible as to where I'm going. Too much pixilation to read it. Any chance of emailing me a larger file. Actual size of this one is about 2x3. I understand the need to keep images small on the forum. If you need my email address. Let me know

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Monday, February 15th, 2010 AT 7:47 PM
Tiny
RACEFAN966
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Should be able to just pm me an e-mail address to send it to.

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Tuesday, February 16th, 2010 AT 8:33 AM
Tiny
JERRYAUSTIN
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Can't pm you. Don't have 10 posts yet. Pbj892@verizon. Net

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Tuesday, February 16th, 2010 AT 3:32 PM
Tiny
RACEFAN966
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Ok it is sent hope this helps. Let me know what you find and we will go from there.

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Wednesday, February 17th, 2010 AT 10:14 AM
Tiny
JERRYAUSTIN
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http://www.2carpros.com/forum/automotive_pictures/479893_Firewall_Manifold_1.jpg



http://www.2carpros.com/forum/automotive_pictures/479893_Extra_line_1.jpg



Couple questions, reference the pictures attached, so I can finish.

1. What are the two ...valves/manifolds on the firewall?
2. Is this a spare vacuum line installed in the harness?
3. Where is the reservoir and check valve?
4. Which vacuum line supplies vacuum to the Temperature blend door? I see electrical wires behind the knob.

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Wednesday, February 17th, 2010 AT 4:57 PM
Tiny
RACEFAN966
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OK the vacuum comes from the intake manifold to the resersior tank (which should be under the hood). There usually is no extra vacuum lines so I would check to see if it is broke and if there is another end to it. Now as the the vacuum solenoids if there are part numbers on it get those to me so I can look them up. I think they will be evap solenoids used for smog stuff.

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Thursday, February 18th, 2010 AT 9:04 AM
Tiny
JERRYAUSTIN
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Solenoids not associated with the heating and cooling then. Been looking through my Haynes manual and there is no mention of the vacuum reservoir. Is it under the battery? How big is it?

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Thursday, February 18th, 2010 AT 11:09 AM
Tiny
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No they are not. I would like you to check the vacuum control for the defrost the floor and fresh air intake. Use the pic to find those. The reservior tank should be under the hood but it won't tell me where.

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Friday, February 19th, 2010 AT 10:08 AM
Tiny
JERRYAUSTIN
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Get back to you next week

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Friday, February 19th, 2010 AT 3:42 PM
Tiny
RACEFAN966
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OK thats fine. Let me know how things go. We will keep at this till we fix it.

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Saturday, February 20th, 2010 AT 9:04 AM
Tiny
JERRYAUSTIN
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Tested the lines by removing the vacuum harness and suppying vacuum individually and found the following:

#3 Black Able to supply vacuum and it held for 1 minute without loss. Released vacuum and hooked up again, then started truck and vacuum supplied by engine measured approximately 21 inches.(Gauge not calibrated)

#1 White Able to supply vacuum and it held for 1 minute without loss. Ran system and supplied vacuum and fan speed increased indicating recirculate door had closed.

#2 Yellow Able to supply vacuum and it held for 1 minute without loss.

#5 Blue Able to supply vacuum and it held for 1 minute without loss.

#6 Red Able to supply vacuum and it held for 1 minute without loss. Ran system in defrost mode and supplied vacuum. Air switched from Defrost to Panel.

Another question. Is the temperature blend door Electrically controlled and vacuum actuated? Diagram shows a full vacuum position but doesn't show a vacuum source to it. Temp switch has 3 wires coming out of the back.

Going back in today and check vacuum under load while driving to verify drop of vacuum pressure and see how much. Will also try adding vacuum to blue and yellow lines to see what results are.

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Sunday, February 21st, 2010 AT 7:18 AM
Tiny
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The blend door motor is electrically controlled. So that is what I would like to test next when you are ready.

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Monday, February 22nd, 2010 AT 10:28 AM
Tiny
JERRYAUSTIN
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Found the reservoir and check valve. Fitting going to line running from check valve to reservoir appears to have had a small crack at the valve (it broke off when looking at it and one side seemed dirty indicating sucking air for a while.). New one on order. Will arrive tomorrow. Go ahead and let me know how to test blend door

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Monday, February 22nd, 2010 AT 11:32 AM
Tiny
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Lets wait till the new reservior tank is put in. If that it no good the test will not be correct.

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Tuesday, February 23rd, 2010 AT 9:07 AM
Tiny
JERRYAUSTIN
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Everything under the hood has been reinstalled. Problem still exists. Did not replace the reservoir tank but did test it. 20" vacuum from tester held for 1 hour. Know there has to be a leak somewhere. Do you know what line provides vacuum to the blend door?

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Wednesday, February 24th, 2010 AT 12:53 PM

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