Heater wont shut off

Tiny
CHILLINS
  • 1997 MERCURY MOUNTAINEER

Heater problem V8 Two Wheel Drive Automatic

when I am driving down the road and I have the heater shut off hot air is blowing into the floor boards of the front driver and passenger of the car. It blows hot air even with the temp turned all the way to cold. It does not blow super strong but does blow and is hot.

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Sunday, August 3rd, 2008 AT 2:08 AM

26 Replies

Tiny
MERLIN2021
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  • 17,551 POSTS

Auto temp control, or manual?

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Sunday, August 3rd, 2008 AT 7:13 AM
Tiny
CHILLINS
  • MEMBER

I assume the auto temp control is digital read out. here is a pic of my dash and behind the dash.


http://www.2carpros.com/forum/automotive_pictures/222398_P1010059_1.jpg



http://www.2carpros.com/forum/automotive_pictures/222398_P1010060_2.jpg

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Saturday, August 9th, 2008 AT 1:00 AM
Tiny
MERLIN2021
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Sounds like the heat control valve on the heater water inlet hose, test this way.


http://www.2carpros.com/forum/automotive_pictures/62217_heata_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_heatb_1.jpg

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Saturday, August 9th, 2008 AT 5:37 AM
Tiny
CHILLINS
  • MEMBER

It does not do it constintly. When the car is stopped at a light you can barely feel any air. But when you are driving down the street then it blows out stronger.

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Saturday, August 9th, 2008 AT 11:22 AM
Tiny
MERLIN2021
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Use a reciculation setting, or max a/c, this will close the flow of outside air off.

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Saturday, August 9th, 2008 AT 11:49 AM
Tiny
CHILLINS
  • MEMBER

That is not going to fix anything. I want to fix the issue not simply make it so I can live with it. Again it is doing all of this when the system is turned to the off position.

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Saturday, August 9th, 2008 AT 12:35 PM
Tiny
LJH2100
  • 1998 MERCURY MOUNTAINEER
  • MERGED

Heater problem
1998 Mercury Mountaineer V8 All Wheel Drive Automatic 184000 miles

Hello, I recently took my truck to the shop because the heater would take a very long time to heat up (about 15 minutes of driving) and my wife said it never heated up on a 45-minute trip she had last week. The shop checked for a coolant leak (as advised by a company that changed my oil) and found there was too much coolant so they removed some. Then they test drove the vehicle and said that it seemed to be working fine and it got lots of heat within 6 minutes. The next two days it surely did work. However, it then reverted back to doing the same thing, the thermometer gauge seems to indicate the vehicle is getting to operating temp but is still not heating. Thermostat needs replaced? Blend door getting stuck?

Thanks

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
KHLOW2008
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Hi ljh2100,

Thank you for the donation.

Perform the following test first.

Check for proper coolant level.
Start engine and turn heater ON.
When engine reaches normal operating temperature, feel heater outlet hose.
It should be hot.
If not heater core may have an air pocket, heater core may be plugged, or thermostat may not be working
properly.

If outlet hose is hot, then problem should be due to blend door.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
LJH2100
  • MEMBER
  • MERGED

Where is the heater outlet hose located? The truck is not here right now but what is involved with fixing the blend door if that is the case?

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
KHLOW2008
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The picture shows the heater hose which have been disconnected.


http://www.2carpros.com/forum/automotive_pictures/192750_HeaterhoseFord_1.jpg



If it is a broken blend door, which is quite common, it can be replaced from under the heater hoses. Normal procedures requires the dash to be removed but some of the guys out there have done it without doing so.


http://www.2carpros.com/forum/automotive_pictures/192750_HeaterhoseFord01_1.jpg



Tip: Broken blend door replacement short cut

You can purchase the door seperately from
Napa(part# BK660-1810) and replace it from under the hood. All you have to do is split the evap case and remove cover, evaporator and accumulator from vehicle to gain access to the hole in firewall so you can get to the door. Next, drop the glove box and disconnect the actuator and get it out of the way so the door will come out. With a small pry bar, gently pry down on the top of the door as close to the pivot point as you can and door will come free. The next thing to do is break or cut the door in half so it will pop right out. If you choose not to do this, you can get it out, but it is a little tricky. Now take the new door and cut a small section off the bottom of door to make installation easier(it will still seal inside case). Start cut 3/8" up from bottom on outer edge and taper down toward bottom edge about 2" from the outer edge. Then put in through the firewall hole and into place. This is a little tricky also, but can be done, do not get frustrated. It will take the same gently prying with the pry bar to get pivot hinge to seat in hole. Reinstall actuator, evaporator, and accumulator and recharge and you are done. After you do a few, you'll be doing them in about 2-3 hours.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
LJH2100
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  • MERGED

How long does a blend door take a mechanic to replace? To me it seems like that would be the most likely scenario given the fact that the heater components do seem to be in working order but I assume the thermostat could be be the issue.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
KHLOW2008
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Based on the procedures described it would take about 3 hours. Removal of the dash and heater housing would take much longer.

If the heater hoses are not as hot as they should be, then it could be a faulty thermostat.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
NDMMAM
  • 1999 MERCURY MOUNTAINEER
  • MERGED

Heater problem
1999 Mercury Mountaineer 6 cyl Four Wheel Drive Automatic 87K miles

The Air from the heater stopped blowing out of the front vents on the dash board and the defroster vents. It works and blows hot air for the back seat vents and the rear window defroster.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
BMRFIXIT
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Check fuses
suspect front blower motor

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
CARLOSFERNANDEZ
  • 1998 MERCURY MOUNTAINEER
  • 160,000 MILES
  • MERGED

My heater works but on blows out at a low setting weather in set it to high or low but my rear one works just fine

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
KHLOW2008
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Can you please rephrase your question?

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
CARLOSFERNANDEZ
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When I turn on the heater it blows out as if it is on the lows setting when I turn it up it still blows out low. My rear unit blows out high and low.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
CARLOSFERNANDEZ
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  • MERGED

While I drive the faster I go it seems to blow out a little faster but really no change. I can only feel it when I put my hands on the vent.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
KHLOW2008
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The air flow is low. If the blower motor noise changes when setting is increased it means air restriction in the air flow circuit. Check the cabin filter if equipped.

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Thursday, May 18th, 2017 AT 1:12 PM
Tiny
CARLOSFERNANDEZ
  • MEMBER
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I will check now and see if that is the problem thanks for the response

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Thursday, May 18th, 2017 AT 1:12 PM

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