No heat

Tiny
TDR8256
  • MEMBER
  • MERCURY MARQUIS
I have a 2004 mercury grand marquis with 91,000 miles (4.6). I have no heat, and this is a problem because its winter! I recently changed the thermostat, but even when I have the climate control on the highest setting (90 degrees) and the fan on high, its still blowing cold air.

The engine runs at normal temperature, does not overheat at all.

Tested the EATC system, as described below and the only code that showed up was 025.

Can anyone tell me where in the dash I can find the air blend door actuator?
Tuesday, November 6th, 2007 AT 1:21 PM

25 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Could be a clogged heater core here is a guide to help you see what you are in for when changing the mode blend door actuator.

https://www.2carpros.com/articles/replace-blend-door-motor

and

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

Check out the diagrams (Below)

Please let us know what you find. We are interested to see what it is.

Cheers
Images (Click to make bigger)
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
+7
Tuesday, November 6th, 2007 AT 3:32 PM
Tiny
DAWADN
  • MEMBER
  • 1 POST
My problem is I have no heat or air working at all, seems as there is no power to the fan or temperature control unit. I remedied this by replace the blend door actuator thanks 2Carpros! I think the cost would be associated with this problem was $265.00.
Was this
answer
helpful?
Yes
No
+3
Thursday, November 29th, 2007 AT 9:20 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Use 2CarPros anytime, we are here to help. Please tell a friend.
Was this
answer
helpful?
Yes
No
-1
Thursday, November 29th, 2007 AT 12:34 PM
Tiny
HOTTMOMMA
  • MEMBER
  • 1 POST
  • 2003 MERCURY MARQUIS
Heater problem
2003 Mercury Marquis V8 Two Wheel Drive Automatic 78k miles

my car has no heat or air whenever I select either have to use the vent selection to stay warm in the cold weather and the fan does not blow with heat or ac selection replaced blower motor but still doesnt work what solution at a dead end, thanks
Was this
answer
helpful?
Yes
No
+1
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
There is a blower motor relay in the power center under the hood near the battery, try swapping it with anothe relay (wipers, A/C) to see if it will come on. If not need to get a test light and see if there is power at the blower motor resistor (right side of firewall near blower motor)
Was this
answer
helpful?
Yes
No
+1
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
TRISHA63
  • MEMBER
  • 2 POSTS
  • 2003 MERCURY MARQUIS
  • V8
  • 2WD
  • AUTOMATIC
  • 700,054 MILES
Heater problem
2003 Mercury Marquis V8 Two Wheel Drive Automatic 700054 miles

The air works. The blowers work. Hoses are fine. Theremastaut is fine

I can't get the heat to work on my 2003 Mercury grand marquis and the dealer said it might be the BLUNT door but I can't find anything about it in the book. The hoses are fine the thermostat is fine. It's not leaking water or antifreeze. I am trying to fix it myself because of the money. Thank Trish
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Trish:
With the engine warm, the hearter on high, make sure both heater core hoses are hot. If they are, I think they are refering to the blender door. It opens to allow heat to pass the heater core and warm the car.
Was this
answer
helpful?
Yes
No
+4
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
TRISHA63
  • MEMBER
  • 2 POSTS
Thank you; I will try that. Trish
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Let me know what you find.

Joe
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
PINKBUNNYMR
  • MEMBER
  • 1 POST
  • 2003 MERCURY MARQUIS
  • V8
  • 2WD
  • AUTOMATIC
  • 70,000 MILES
I have a 2003 Grand Marquis that is blowing air but will not get hot. I've checked the thermostat, anti freeze, and fuses. From what I gather there is a blend door valve that is prone to going bad and is coincidentally expensive to replace. Where is it and can I force it manually without replacing it?
Was this
answer
helpful?
Yes
No
+6
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the heater control valve and the heater core-if okay then deal with the air blend door/vacuum and actuator
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
SKYKINGTUTT
  • MEMBER
  • 3 POSTS
  • 2003 MERCURY MARQUIS
  • 107,000 MILES
I took it to the dealer and they said the problem was the blower fan, well I replaced it nd it still doesnt work. Ive checked all of the fuses ans I checked the relays. I figured out that the electrical current is not getting the the motor but I have no idea what to check next. Wha would be the most likely problem be? Thank you
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Find the power wire to the blower motor and power it direct from the battery and see what happens -start here
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
Do you have manual or automatic controls.
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
SKYKINGTUTT
  • MEMBER
  • 3 POSTS
How do I hook the power wire up to the battey? What is th differanc between auomaic contrls and manual? Im not sure what I have.
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
On auto you set temp # and it holds temp at that setting by auto manipulating other control factors.
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
On manual system, your blower is ALWAYS HOT with mode switch anywhere but off. So check blower for hot wire good 12v. Your mode switch grounds blower relay(turns 12v on) and your blower switch grounds blower motor to make it run. Relay is by battery in junction box.
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
SKYKINGTUTT
  • MEMBER
  • 3 POSTS
Ok then I have auto.
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
GASMAN5811
  • MEMBER
  • 1 POST
I had this same thing happen to me. It was the blower motor control resistor. You probably do not want try to tackle this yourself. I watch the service tech who had every tool you can think of battle it for about an hour. There are some plastic clips that if you break them you have to replace the whole line. Only cost me 378.00 to get fixed at a/c shop and I was in the Florida Keys on vacation. So it's not worth risk.
Was this
answer
helpful?
Yes
No
Tuesday, January 16th, 2018 AT 4:07 PM (Merged)
Tiny
MLOSOYO
  • MEMBER
  • 1 POST
  • 2003 MERCURY MARQUIS
  • V8
  • FWD
  • AUTOMATIC
  • 92,540 MILES
Air Conditioning problem
2003 Mercury Marquis V8 Front Wheel Drive Automatic 92540 miles

my air and heater are not working, I can feel the cold air but it won't blow out same for my heater it just doesnt blow out, we connected the fan for the heater and the air conditioner directly to battery and it work, I am starting to think it my be the switch that turns the air and heater on, also my radio has alot of static that I cannot hear and my windows switches are having trouble lowering the windows and also my lighting no longer works it worked a week ago and now it doesnt, could I be having an electrical problem.
Was this
answer
helpful?
Yes
No
+1
Tuesday, January 16th, 2018 AT 4:08 PM (Merged)

Please login or register to post a reply.

Related Heater Not Working Content

Heater Not Working
VIDEO
Heater Not Working
Instructional repair video
Heater Not Working
GUIDE
Heater Not Working
Step 1 - A heater cannot operate unless the engine is full of coolant/antifreeze. If coolant level is low check the system for leaks.
VIEW MORE