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.
Heater Stuck on Hottest Setting Due to Broken Heater Blend Door on Mercury Mountaineer
Average mileage: 121,514 (15,000–230,000)
82 people reported this problem
42 people shared problem details
2001 Mercury MountaineerVisitor
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.
heater blend door not working. found broken vacuum line between firewall and engine. Repaired with plastic tape now works fine.
2005 Mercury Mountaineer182,000Visitor
Blender door open on cold side. Not good timing in winter.
2005 Mercury Mountaineer167,000Visitor
Its actually stuck on cold with a click sound
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
2003 Mercury Mountaineer124,000Visitor
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
2005 Mercury Mountaineer137,770Visitor
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!!!!!!
2003 Mercury MountaineerVisitor
Blender door broke - no heat in front of vehicle
2007 Mercury Mountaineer82,000Visitor
passenger side air conditioner blows hot air.
1997 Mercury Mountaineer222,500Visitor
No Heat in side Mountaineer.
2003 Mercury Mountaineer117,000Visitor
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.
Air conditioner ;lows heat on passenger side. Driver side cool.
2004 Mercury MountaineerVisitor
Problem with the heater blend actuator. When I want heat only cold air comes out. Makes a clicking sound all the time. I got if fix before and it worked for a while then it started again.
2004 Mercury Mountaineer110,000Visitor
Hasn't been fixed yet but reading the source of the same problem of my vehicle not blowing hot air, let's me know it's the actuator.
1997 Mercury Mountaineer15,000Visitor
I had this repaired already and now 5 years later I am having to do it again! The first one cost me over $600.00 and now I am having to do it again? Cheap product!
2005 Mercury Mountaineer65,000Visitor
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.
2005 Mercury Mountaineer124,000Visitor
Won't switch from air to heat at all. I haven't had it repaired yet so I'm not sure of the cost. Sounds expensive.
2004 Mercury Mountaineer90,000Visitor
My defrost stopped working properly. A short time later, I heard a clicking sound and neither my heat or air are working.
1998 Mercury Mountaineer196,000Visitor
vent door needs replaced
Air conditioner blows hot air on passenger side
my heater blows warm air then cold air,it keeps alternating when i have the heat on
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