Question about Ford Expedition

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1999 expedition 5.4 cold air from dash vents, hot air from rear vents with a/c on max and all fans wide open. any thoughts? Comments: Apr 23, 2010 - thanks pal. just charged the system and moments ago verified system operating pressures, so i will rule out answer two at this time. the mix door idea is intriguing... there must be separate mix doors front and rear? is that possible? Apr 23, 2010 - i'm having trouble visualizing a problem with the mix door. if there is only one mix door, why would i get 44 degrees temp from one vent and ambient temp from another? are there more mix doors on this vehicle? Apr 25, 2010 - ok, one more time... please answer only if you are an expert. the system operates with 2 evaporators; front and rear. front blows cold, rear does not. system operating pressures are normal; both high and low pressure sides. it's not a 'mix' door problem. the issue is that the rear evaporator does not get cold. is it definitely supposed to, at all times? what would make it evident that there is a blockage at the rear expansion valve? what could cause one evaporator and not the other to get refrigerant flow?

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  • ian brenner Apr 25, 2010

    thanks for your time and effort!

    please forgive me beating a dead horse, but i need to ask again:

    the issue is that the rear evaporator does not get cold. is it definitely supposed to, at all times? what would make it evident that there is a blockage at the rear expansion valve?

    i have come to the same conclusion you have, but i need to know why for certain.

  • ian brenner Apr 25, 2010

    TYVM! again, i appreciate your time and effort!

  • ian brenner Apr 25, 2010

    roniecon knows his stuff!



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The expansion valve on the rear evaporator is not opening,or it is all the way open,replace the expansion valve on the rear evaporator to correct the problem,this is pretty common for this to happen.The expansion valve is connected to the evaporator in the rear unit,this is the problem.

Posted on Apr 25, 2010

  • Ronny Bennett Sr.
    Ronny Bennett Sr. Apr 25, 2010

    This is,the only solution,there is no way to check on pressures sense they vary to out side temp,and the system is set up parrall in stead of inline,and all of them are,but this is the problem trust me,I do this for a living.

  • Ronny Bennett Sr.
    Ronny Bennett Sr. Apr 25, 2010

    If this was helpful,please let them know,and I thank you.



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