Heater Stuck on Hottest Setting Due to Broken Heater Blend Door on Mercury Mountaineer

A failed heater blend door or actuator can cause the temperature control for the HVAC system to stop working. A clicking sound from the dash area would commonly indicate an actuator fault. If the heater gets stuck on the hottest setting, the heater blend door may be broken requiring replacement of the heater box to repair the issue.

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Average mileage: 123,756 (44,000–230,000)
14 model years affected: 1997, 1998, 1999, 2000, more2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
74 people reported this problem
35 people shared problem details
heater blend door not working. found broken vacuum line between firewall and engine. Repaired with plastic tape now works fine.
7 people like thisFlag inappropiate
first there was a clicking sound, then the heat was stuck on the hottest setting. have called around town and its looking like $340 plus to fix. This is a very common problem with Fords. If the company knows this, they should fix it for free or discount a repair at the dealership. why keep making cars that are gonna have the same problem.
6 people like thisFlag inappropiate
Its actually stuck on cold with a click sound
5 people like thisFlag inappropiate
Blender door open on cold side. Not good timing in winter.
5 people like thisFlag inappropiate
Mine was stuck on heat-no AC-bought aftermarket blend door online-after taking dash out found orig OK, but actuator motor broken.bought one at a national parts place, it wouldn't work, took to shop they replace w/ford actuator-now works, but knob to regulate air flow does not work, will cost another $600 to repair-don't have the $$ to do so
4 people like thisFlag inappropiate
Just purchased from local ford dealership, two days later clicking sound in heater.. took into service dept and was told not to worry about it... now two days later I have no heat.. taking in tomorrow to see what they will do for me
4 people like thisFlag inappropiate
Blender door broke - no heat in front of vehicle
3 people like thisFlag inappropiate
clicking when changing to heat, as far as I can tell the blend door actuator gear must have some stripped out teeth on it. The actuater being replaced should fix the problem.
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No Heat in side Mountaineer.
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My heater started making a loud noise and then it finally went out. I replaced the blend door actuator several times but they kept going out. Everytime I put the actuator in the only thing that will works is my heater. So if I unplug the blend door actuator my air conditioning works. If I plug the blend door actuator in the heater works and my air conditional won't. So in order for me to have air I have to unplug my blend door actuator every summer and in order for me to have heat I have to plug my blend door actuator back in everyone winter which means I have to buy a new one every winter. It's so frustrating don't nobody know what's going on or how the fix the problem please help me!!!!!!
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blend door thumps and has troble changing from warm too cold.not fixed dealer told me it will cost a thousands dollars to fix it.
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My problem wasn't the heat it is the cold. The shutter door is stuck on cold air instead of hot I did not fix it I do not drive the vehicle very often. Other family members use it for small jobs and moving things around because of the towing bar. I was told it would be very costly to go in the dash to fix
Air conditioner ;lows heat on passenger side. Driver side cool.
Doesn't get cold enough or hot air comes out
passenger side air conditioner blows hot air.
No air flow from heater through defrost, floor or dash vents.
turn on ac its hot then I put on maxac and it gets cold.
passenger side temperature control not working. do not know if pneumatic, electric or mechanical problem
Air conditioning blows hot air.
No heat or cool air. I must keep the dial on the coolest setting or I will get a click click click click noise until I turn it back to the coolest setting.
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