Question about 2002 Mercury Grand Marquis

1 Answer

2002 Mercury Marquis Heat only comes out vents

After changing the battery only heat comes out. when the air cond. is turned on I can hear the compressor engage. I think the door? on the vent system is stuck. After hooking up the battery a thumping noise was heard behind the dash. How do I get behind the dash? Thanks for any help TK

Posted by on

  • Mark0707 Mar 09, 2009

    I have the same problem with a 1996 Grand Marquis. Heard some clicking noises, then nothing but full heat would come out of the vent.

  • milestriano May 19, 2009

    I have a Grand Marquis 2002 and recently the air conditioner is not working properly. I don't know much about cars, especially ones with as many electronics systems as mine. I have read other blogs and one said if you changed your battery it is possible for a system in the car to burn out. I am not rich and wondered what could possibly be the problem so that when a mechanic does a diagnostic I don't seem completely ignorant. My car is a luxury edition and has climate control.


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Mercury Master
  • 5,386 Answers

There could be a thermal switch for blower speeds and temp. Since you needed to replace the battery, the thermal switch could have run down the battery. When you restored a dead battery with a fully charged battery a resistor blew. There is a cover underneath the glove box that can be removed and the glovebox lid can easily be unclipped to hang out of the way. Just look at the sides of the glovebox and you will see brackets which can be pinched to let the lid hang down. Unplug the switch and look for melted parts.

Posted on May 03, 2009

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer


Are the battery and starter working properly? no heat could be air in the cooling system. Bleed that once you get it running.

Dec 09, 2013 | 2002 Mercury Grand Marquis

1 Answer

My Air cond, heat and vent doesn't work at all on my car. I have replaced fuses and the blower motor. Whenever I put the new motor in it would run then blow the fuses. Could it be the compressor?

No, the compressor will NOT cause these fuses to blow. You have a SHORT in your electrical system. you have a HOT wire getting into the Ground for that system

Apr 09, 2013 | 2002 Mercury Sable

1 Answer

No heat from vents

As per your problem mentioned. There are few solved help links to troubleshoot these problems. Go through the list and Click the link below:----

2000 Toyota Avalon: No heat on Passenger Side?


No heat on Oldsmobile Silhouette?


Heater blows cold?


Heat blows cold on drivers side and hot on passenger side?


Hot air on the driver's side vents only?


Temperature gauge does not move and no heat when heater is ON?


1992 Toyota Camry: A/C Control light Flashing and A/C not Blowing Cold?


No heat, blower blows only cold?

Ford F150 Ac only blows through defrost vents?


Dodge A/C come out of defrost vents only?


Ac vacuum line on dodge cummins?


Ford ranger AC blows cold through defrost vents instead on cabin vents?


2005 Chrysler PT Cruiser: A/C Blows Warm?


2009 Mercury Grand Marquis: A/C blows Cold From Defrost Vent Only?


AC not blowing through Vents on 2007 Chevy Trailblazer?


Passenger side temperature is warm air out of dash vents?


These will help.


Nov 28, 2012 | 2006 Ford Taurus

1 Answer

I have no heat blowing into my 2002 Mercury Grand Marquis.

Sounds like there is no coolant flowing INTO the heater core to me. There is usually a valve that opens to allow coolant to pass thru the heater core. some are electrical, some are vacuum operated. My suspicion is that you have a bad valve, or no power or vacuum supply to that valve.

Jan 13, 2012 | 2002 Mercury Grand Marquis

1 Answer

Cannot change temperature on heat & air

Temp is controlled by an electric motor(or could be vacuum hose) on the blender door of heater housing. If you find this is operating correctly, then the problem is a plugged heater core.Backflush it by removing both heater hoses and flushing from water pump side toward thermostat side.don-ohio

Oct 23, 2011 | 2000 Mercury Grand Marquis

1 Answer

Cannot adjust temperature on the heat & air, 2000 grand marquis, cannot get any heat, air cond temperature cannot be adjusted, it stays on cold at all times

Is this an automatic temp. control or manual heater control? if it's automatic control,it can be an expensive circuit board which has gone bad. don-ohio

Oct 22, 2011 | 2000 Mercury Grand Marquis

1 Answer

I dont know how to turn the heat on in my 2002 grand marquis

Try setting the climate control to "Automatic," then raise the temperature until the display reads what you want, like 72 or 74 degrees. The heat will come on automatically and adjust by itself when the temperature you set is reached. You can also push the "Floor" or :Defrost" button and this will turn the heat or defrost on manually.

Nov 10, 2010 | 2002 Mercury Grand Marquis

1 Answer

Air cond warm coming out of driver side dash,warm passenger side

you want me to post a free solution yet want to charge for info I requested for free?

Jun 18, 2009 | 2002 Cadillac Deville

1 Answer

My air condition is not blowing air out the vents.

Sparking meaning your socket maybe not secure or lose connection. sometime the carbon brushes in blower worn out and need to change.

Jun 09, 2009 | 2001 Mercury Grand Marquis

Not finding what you are looking for?
2002 Mercury Grand Marquis Logo

171 people viewed this question

Ask a Question

Usually answered in minutes!

Top Mercury Experts


Level 3 Expert

71231 Answers

Ron Lankford

Level 3 Expert

5386 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22059 Answers

Are you a Mercury Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides