2003 explorer 4.6l defrost problem
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2003 explorer 4.6l defrost problem
hi I have a 03 explorer and when on defrost if i turn the temp to hot it changes from defrost to heat, also if i lower the temp setting a little it goes back to defrost,this has manual heater control and i replace the control head and did not help with this issue. anyone know anything about this issue please help.
Logistics Pro
Joined: Jun 2009
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From: Cedar Rapids, IA
Welcome to the forum!
Are you saying that if you set the temperature selector to the hottest (red) settings the air stops blowing on the windshield and switches to blowing out the vents? If not, what do you mean by "changes from defrost to heat"?
-Rod
Are you saying that if you set the temperature selector to the hottest (red) settings the air stops blowing on the windshield and switches to blowing out the vents? If not, what do you mean by "changes from defrost to heat"?
-Rod
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Joined: Jul 2005
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i doubt the temp **** has anything to do with it, just a coincidence. THE air position is controlled by vacuum cylinders. If you loose vacuum the system shifts to defrost position from the vents or floor.. YOu can loose vacuum by touching the throttle (gas pedal) and by having a vacuum leak in an air hose. I would look under the hood at all the small black vacuum hoses on the intake manifold and around the EGR valve. THEy get hot and cracked. It can be the hoses under the dash on the cotrol ****, but unlikely unless you have been moving things around up there. Since you replaced the conroller, i would not assume bad o-ring seals, or bad hoses in that area. Look under the hood.
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steve the first control head would cause it to go from blowing on the windsheild to the floor when moving the temp setting from hot to cold, I thought there was something wrong in the electronics part of the control head causing it to do that, so I replaced the control head, now with the new unit it still does the same thing, cannot find any info on fords tech site to explain how the electronics control the vacume part of it. I didnt think it was a vacume issue because when on defrost and temp on hot everything is suppose to be at no vacume, thats why i tried the control head first. Thanks for all the help, I will contue to search for the cause of this issue and post what I find.
Logistics Pro
Joined: Jun 2009
Posts: 4,817
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From: Cedar Rapids, IA
With the manual HVAC system, the only electrical component that has to do with the air flow is the blend door actuator. But even that won't impact which vents the air flows from. The heater control valve is vacuum actuated and, with no vacuum, should be full flow.
Has the air flow ever functioned correctly since you owned the truck? What are the chances that somewhere along the line someone played with the vacuum lines to the HVAC system and didn't get them quite correct?
-Rod
Has the air flow ever functioned correctly since you owned the truck? What are the chances that somewhere along the line someone played with the vacuum lines to the HVAC system and didn't get them quite correct?
-Rod
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