2005 Chrysler Pacifica 2005 Pacifica defrost does not work

Tiny
GARYS712
  • MEMBER
  • 2005 CHRYSLER PACIFICA
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 98,000 MILES
I have a 2005 Chrysler Pacifica. The defrost has given me fits the last two winters. I have spent 1000 dollars at a dealership and once again my defrost is not working. The heater works and so does the fan control speed. My AC vents continue to blow air. The floor vents do not blow air either. Last spring the mechanic said he fixed the problem and replaced a black wallet sized plastic part with a gear in the middle. My wife went to start the car after she paid and the defrost did not work. The mechanic reached under the dash and did something and it started to work. I also had the battery replaced 8 months ago and had no problems until after a week long trip where we mostly drove and stopped and looked at things in Wisconsin. Just to check a hunch I went and checked the battery. It was fine just now. And just to test another one I unhooked the battery and then rehooked it up. All the controls then worked properly. What in the blazes do you think is happening. The last thing I want to do on a cold winter morning is mess with the battery so my defrost works. Thanks!
Saturday, August 29th, 2009 AT 3:17 PM

10 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
May need to be re-calibrated, and check the connectors by wiggling them when the door dosent re direct the airflow to the defrost setting. A/C-HEATER CONTROL CALIBRATION The A/C-heater control module must be recalibrated each time an actuator motor or the A/C-heater control is replaced. If the vehicle is so equipped, the calibration procedure also includes rear HVAC positions for each actuator motor. 1. Turn the ignition switch to the On position. 2. If equipped with the manual temperature control (MTC) system, press and hold the Power and Recirculation buttons for at least five seconds. If equipped with the automatic temperature control (ATC) system, simultaneously press and hold the Power and Recirculation buttons on the A/C-heater control for at least five seconds. The MTC A/C-heater control Power button light emitting diode (LED) and Recirculation button LED, or the ATC A/C-heater control Delay and Recirculation graphics will begin to flash when the calibration procedure has begun. 3. The calibration procedure should take less than two minutes to complete for the manual A/C- heater control, and less than twenty seconds for the ATC A/C-heater control. When the LEDs or graphics stop flashing, the calibration procedure is complete. 4. If the LEDs or graphics continue to flash beyond the two minute (manual) or twenty second (ATC) calibration time, it indicates that the A/C-heater control has detected a failure and a Diagnostic Trouble Code (DTC) has been set. Refer to BODY DIAGNOSTIC PROCEDURES to perform further diagnosis. The LEDs or graphics will continue to flash even after the ignition switch is cycled Off and On, until a successful calibration is completed or until the vehicle has been driven about 13 kilometers (8 miles).


https://www.2carpros.com/forum/automotive_pictures/62217_Pacificaa_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_pacificab_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_pacificac_1.gif


The other thing is, there is a tech bulliten about the a/c drain draining water to the passenger floor, instead of out of the vehicle, check the rugs on that side, are they wet?
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Sunday, August 30th, 2009 AT 7:31 AM
Tiny
GARYS712
  • MEMBER
  • 9 POSTS
Thanks for the reply! The diagrams show exactly the piece that was replaced. The passenger side is dry. At least so far. I will try the steps you sent and let you know how it turns out. Thanks for the information and diagrams. I really appreciate it!
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Sunday, August 30th, 2009 AT 9:17 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Your welcome Gary, and thank you for the points!
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Sunday, August 30th, 2009 AT 9:32 AM
Tiny
GARYS712
  • MEMBER
  • 9 POSTS
: ) Here's another stupid question. The diagram. Is it from under the dash or the hood? If under the dash is it the passenger side? Thanks again!
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Sunday, August 30th, 2009 AT 9:54 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Frm under the dash, these actuators are screwd on to the plenum(black Box) of the heater/a/c unit. Runs from passenger side to about the middle next to the gas pedal.
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Sunday, August 30th, 2009 AT 10:24 AM
Tiny
BMINTZER7
  • MEMBER
  • 1 POST
Were you able to fix the problem? My 2004 Pacifica just had the same thing happen, the defroster and floor blower stopped working.
I haven't had any work done on it as of recently, battery or otherwise. I'm scheduled to bring it to the garage on Monday, but would love to be able to fix it myself if at all possible. Please let me know. Thanks.
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Friday, November 19th, 2010 AT 6:19 PM
Tiny
YAR
  • MEMBER
  • 1 POST
Have had this defrost problem several times over the years and surely paid hundreds for techs to research. It always comes back in a year or two. THird time it happened Oct 2011 I got on the internet and fond someone who suggested cleaning the battery terminals. IT WORKED!

Obviously the HVAC controller is very voltage sensative and the recalibration does not work if the voltage is a little low.
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Saturday, October 29th, 2011 AT 9:32 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Thanks for the input, it would be helpful for others.

Have a nice day.
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Sunday, October 30th, 2011 AT 6:56 AM
Tiny
DOUG.O
  • MEMBER
  • 2 POSTS
I just found something out. I have been having problems with my defroster would not work on my 2005 Pacificia, I checked everything and was surprised on what I found. Under the battery there is a plunger and when the battery is installed the battery sits on and closes that plunger. I removed the plunger switch and cleaned it ( careful not to damage the delicate spring that compresses) I also added two pieced of square Velcro on to p of the valve to make shire the battery was pushing it down. After I was done the heater defrost is working perfectly again. This info may help many when the heater control dose not change to the defrost or floor mode.
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Wednesday, December 13th, 2017 AT 2:17 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Nice work and we really appreciate the input. Thank you.
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Friday, December 15th, 2017 AT 7:28 AM

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