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2005 Mercury Grand Marquis cabin temperature too high in winter
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THeiland
New User
Dec 22, 2008, 7:49 AM
Post #1 of 2
(2375 views)
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2005 Mercury Grand Marquis cabin temperature too high in winter
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I finally have to turn the automatic temperature control off at 80 degress when set to 65 degrees. It appears that the fresh-air intake is not blending with the car's interior cabin air. If I close the damper found on the lower right under the glove box and force re-circulation, it works Ok, but now have too much humidity and not providing any fresh air while driving. Once the damper is closed, setting the temperature in the cabin works properly for both heating and cooling.
It's as if there is no contraint on the air coming from outside the car. If I don't touch the damper for fresh-re-circulate, the heater continues heating at highway speeds and, after getting home and stopped in the driveway, the temperture is managed correctly. I've disconnected the while hose on the inside of the cabin found at the firewall that direct air to the interior temperature sensor and it is cold air. Closing the fresh air-re-circulate damper then forces cabiun air into the blower and the air coming out of the hose matches the temperature in the cabin.
It seems to me to be a problem with too much fresh air coming into the system, but I don't have any idea on how to correct it.
Again, this is a 2005 Grand Marquis with 60,000 miles.
Any ideas would be appreciated.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 22, 2008, 8:54 AM
Post #2 of 2
(2372 views)
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Re: 2005 Mercury Grand Marquis cabin temperature too high in winter
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First off I don't know the specific dash controls you have in this new of a car. Since the get go of "Climate Control" aka "ATC" in a moving vehicle is a bit boneheaded. So many possible triggers to fool it are possible it's rarely handy IMO.
I do suggest you not fool with vents or ducts that aren't meant to adjust. The whole "humidity control" myth is close to just that - a myth!*
Generally speaking: Air to be heated is sourced from outside (fresh) air - rarely recirculated no matter what your request may try to offer. Even on "recirc" about 1/2 the air is fresh anyway.
You said it works when sitting idle so it's just getting fooled by something. Make sure stuff (any add on items?) isn't stuck on dash or item in the way of sensors and if no help there just use manual fan control and direct heat to floor - NBD.
If you have any snow or ice on the vehicle it may not get accurate info or give the best airflow which comes from up by wipers. If so - stuff you can't clear will usually melt when car is shut off! Handy detail
*Myth: Humidity is naturally low when temp drops below the freezing point. Air conditioned air is taking away humidity when humid air passes thru a coil (evaporator) with a temp below the dew point of air passing thru it. Trouble is the air conditioning will automatically shut down compressor if below about 40F and rather quickly so it can only have a very small range of conditions where it could be of any help at all.......
T
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