2003 Mercury Mountaineer Heater not working

Tiny
L. GRIFFIN
  • 2003 MERCURY MOUNTAINEER

Heater problem
2003 Mercury Mountaineer 6 cyl Four Wheel Drive Automatic 105000 miles

When the heater is turned on, there is no heat blowing.

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Tuesday, November 3rd, 2009 AT 8:24 PM

20 Replies

Tiny
RICKMAR
  • MEMBER

You possibly have a "Blend Door Actuator" problem.

I hope I am wrong. It is a pretty expensive repair, not the part you need but the labor !

If it is the blend door actuator and you do not want to pay $1000.00+ for the repair ( I don't blame you at all) and you can do a little mechanical labor yourself there "is" a way to avoid all the dis-assembly which is involved by.
(Cutting a hole in your heater core box) to gain access to the blend door.
That is what I sure would do, without a doubt.
If you want to know how to do it just let me know and I will get the information of cutting that hole right to you.
Good Luck;
Rick

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Friday, November 13th, 2009 AT 9:55 PM
Tiny
RICKMAR
  • MEMBER

What is it doing, blowing just cold air?

If it is you could possibly have a blend door actuator problem.
The actuator is not moving the door in the direction it needs to go to receive the hot air from the heater core.
It is a very popular problem with Explorers and Mountaineers. I am surprised that through the years Ford/Lincoln/Mercury has not corrected the issue.
Rick

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Sunday, November 15th, 2009 AT 5:48 PM
Tiny
MDEVLIN
  • MEMBER

My 2003 Mountaineer is doing the same thing. Since we just got the truck out of the repair shop (yesterday) for rebuilding the tranny I really don't want to pay the $1000+ to repair. Merry Christmas to me! Could you send me the instructions on cutting that hole? And will this hole cause any other problems?

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Thursday, December 17th, 2009 AT 8:13 AM
Tiny
MDEVLIN
  • MEMBER

Found them on another thread.

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Thursday, December 17th, 2009 AT 8:15 AM
Tiny
RICKMAR
  • MEMBER

Yep... the whole dash needs to be removed, $1000+ mainly for labor.
It has been going on for 10+ years and Ford/Lincoln/Mercury has not improved the design ....the S.O.B.'s
Here is the link for the quick fix if you want to do it yourself:

http://www.2carpros.com/articles/mitchell1eautorepair-car-repair-manuals

There "is" another way and that is cutting a hole near the heater core and using duct tape to seal it back up after the repair is done. I will see if I can track that one down and post it here.

THE HOLE WILL NOT CAUSE ANY PROBLEMS AT ALL

Good Luck;
Rick

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Thursday, December 17th, 2009 AT 9:31 AM
Tiny
GEOGARDNER
  • MEMBER

Would please send instruction on cutting the hole in - to access heater blend door on my 2003 mountaineer.

George (geogardnerone@yahoo. Com)

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Saturday, January 7th, 2012 AT 12:27 AM
Tiny
JGAULIEN
  • MEMBER

Blows out same on all 4 speeds lil warm wont switch to defrost floor or vents

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Saturday, February 11th, 2017 AT 9:28 AM
Tiny
2CARPROS KEN
  • ADMIN
  • 6,941 POSTS

Hey JGAULIEN,

There is a blower motor speed controller that has probably gone out, here is a wiring diagram and guide so you can do some testing.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

and

https://www.2carpros.com/articles/car-heater-not-working

Please run some tests and get back to us so we can continue helping you.

Best, Ken

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Wednesday, February 15th, 2017 AT 9:47 AM
Tiny
JAYCEE12345
  • 2003 MERCURY MOUNTAINEER
  • MERGED

Heater problem
2003 Mercury Mountaineer V8 All Wheel Drive Automatic 78000 miles

heat does not blow out only warm air what could be the problem

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Wednesday, February 15th, 2017 AT 9:48 AM
Tiny
BMRFIXIT
  • EXPERT
  • 19,503 POSTS
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As a 1st step you need to start with the thermostat
check it and check its operation
if in doubt replace it

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
  • 2003 MERCURY MOUNTAINEER
  • 120,000 MILES
  • MERGED

Have no heat at all

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
WRENCHTECH
  • EXPERT
  • 20,765 POSTS
  • MERGED

With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If they are both hot, the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
JOEYLUGNUT
  • 2002 MERCURY MOUNTAINEER
  • 96 MILES
  • MERGED

About 6 months ago every time I used my heat it would begin with a loud clicking noise that eventually went away in a few minutes. As of today I have no heat it only blows cold air. Do you have any ideas or suggestions. Thank you

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
RASMATAZ
  • MEMBER
  • MERGED

Check thermostat if its stuck open and the heater core if its clogged-start here

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
MANDO2123
  • 2004 MERCURY MOUNTAINEER
  • MERGED

Heater problem
2004 Mercury Mountaineer V8 Four Wheel Drive Automatic 62000 miles

on my truck the heater doesn't heat when its on parking mode only when Its runing the air comes hot.
The blower its working.
Had antifreeze
I replace the thermostat and still don't heat in parking mode

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
JACOBANDNICKOLAS
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Are you sure the coolant is full?

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
RUSSELL14022
  • 2004 MERCURY MOUNTAINEER
  • 6 CYL
  • AWD
  • AUTOMATIC
  • MERGED

2004 Mercury mountaineer 4.0 v6 awd

The hot air will not work. It will only blow cold air but it is blowing therefore I know the blower is working. I checked the coolant and also replaced the thermostat. I'm not sue if the radiator needs to be flushed or if it's something with the heater core but I am stumped at this point. Any advice would be greatly appreciated. Thanks

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
WRENCHTECH
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With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If not too hot to hold, then you have to look at the actual engine temp and if that is up, if it is, then your looking at a restricted heater core.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
  • 2004 MERCURY MOUNTAINEER
  • 102,000 MILES
  • MERGED

The heat is not working it makes a clicking sound when u turn it on. And the clicking sound is coming from the middle blower in the front in between the driver and passager. The one's that r by the radio

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Wednesday, February 15th, 2017 AT 9:49 AM
Tiny
HMAC300
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  • 48,695 POSTS
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It's probably the actuator is broken or not moivng the piece inside the heater box. You'll have to check to see if it's working. If the actuator works then tehheater box has to be torn apart to fix the broken vent piece. Chek c number 1 on chart.

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