How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Chuck Your Own Question

Chuck
Chuck, ASE Certified Technician
Category: Mercury
Satisfied Customers: 2100
Experience:  33 Years experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance
Type Your Mercury Question Here...
Chuck is online now
A new question is answered every 9 seconds

2004 mercury marquis auto. temp. control.

Resolved Question:

2004 mercury marquis auto. temp. control. air blowing from defroster vents only
Submitted: 5 years ago.
Category: Mercury
Expert:  Chuck replied 5 years ago.

Your problem is a vacuum leak. Defrost is the default postion(no vacuum).Start first by finding the small black vacuum line going thru the firewall near the heater hoses to the heater core. Trace it back to the vacuum reservior located near the relay module and from there to the intake manifold and inspect for leaks.Here or pics of the reservior and how to replace it if you find it leaking. If all of this is good then one of the hoses inside from the control panel to one of the vacuum door motors or one of the motors themself are leaking.

 

 

1.Remove the relay module

graphic

 

2.Disconnect the vacuum hose

 

 

graphic

 

3.From inside the LH wheel well, remove the nuts

 

 

 

graphic

 

 

 

 

Expert:  Chuck replied 5 years ago.

Yes it still does use vacuum even on the electronic system just the blend door is electronic.

 

Control System Outputs-EATC

A/C Blower Motor Speed Control

The A/C blower motor speed control is located on the A/C evaporator housing, in the engine compartment.

  • The function of the A/C blower motor speed control is to convert low power signals from the electronic automatic temperature control module to a high current, variable ground feed for the blower motor.
  • Blower motor speed is infinitely variable and is controlled by the electronic automatic temperature control module software.
  • A delay function provides a gradual increase or decrease in blower motor speed under all conditions.

A/C Electronic Blend Door Actuator

The A/C electronic blend door actuator is located on the top of the plenum housing.

  • Its function is to move the air temperature blend door on command from the control assembly.
  • The A/C electronic blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the air temperature blend door.
  • A 5 volt signal is applied to the ends of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the electronic automatic temperature control module and is matched with the wiper voltage of the module potentiometer. The control module then drives the actuator motor in the direction necessary to make the actuator wiper voltage agree with the control module wiper voltage.

Vacuum Control Motors

Vacuum control motors are used to move the floor/panel and panel/defrost doors.

Chuck, ASE Certified Technician
Category: Mercury
Satisfied Customers: 2100
Experience: 33 Years experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance
Chuck and 5 other Mercury Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on. Rich D USA
< Last | Next >
  • AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on. Rich D USA
  • Because of your expertise, you armed me with enough ammunition to win the battle with the dealer. They are installing a fuel filter and fuel pump at no charge to me. Molly USA
  • I needed help with my car on Saturday morning....got a response in 5 minutes, and it was the perfect solution. Thanks again to your service. Jason V. Kirkland, WA
  • I do know, after going though this with JustAnswer, that I can somewhat trust my mechanic but I will always contact you prior to going there. BR New Jersey
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
 
 
 

Meet The Experts:

 
 
 
  • Ron

    ASE Certified Technician

    Satisfied Customers:

    1601
    ASE Certs and Ford Certs
< Last | Next >
  • http://ww2.justanswer.com/uploads/FO/fordguy4u/2011-12-17_222940_HPIM1257.64x64.JPG Ron's Avatar

    Ron

    ASE Certified Technician

    Satisfied Customers:

    1601
    ASE Certs and Ford Certs
  • http://ww2.justanswer.com/uploads/MU/muddyford/2012-6-13_1204_1.64x64.png Chris (aka- Moose)'s Avatar

    Chris (aka- Moose)

    Mercury Technician

    Satisfied Customers:

    1399
    16 years experience with Mercury
  • http://ww2.justanswer.com/uploads/JM/jmcdo28/2012-2-23_01655_resized.64x64.jpg John Mc's Avatar

    John Mc

    Mercury Technician

    Satisfied Customers:

    403
    19 years Ford Lincoln Mercury experience
  • http://ww2.justanswer.com/uploads/wmarti7/2009-4-18_04332_Avatar.jpg Chuck's Avatar

    Chuck

    ASE Certified Technician

    Satisfied Customers:

    287
    33 Years experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance
  • http://ww2.justanswer.com/uploads/scottz136/2008-12-09_220350_js640_p1010013.jpg scottz136's Avatar

    scottz136

    Mercury Technician

    Satisfied Customers:

    260
    senior master lincoln mercury tech.
  • http://ww2.justanswer.com/uploads/TI/tim37857/2011-10-28_23053_S6301814.64x64.JPG Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    257
    Have owned a repair shop for 25 yrs.
  • http://ww2.justanswer.com/uploads/DR/drivefast1971/2012-1-12_172422_0009051tQKh.64x64.jpg Ron Z.'s Avatar

    Ron Z.

    - Mercury Tech -

    Satisfied Customers:

    197
    18+yrs experience. State Inspector and Mercury Diagnostics