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Actuator door stuck on heat?


9723

Well-Known Member
Joined
Oct 22, 2008
Messages
324
Vehicle Year
1997
Engine
2.3 (4 Cylinder)
Transmission
Manual
I have a '97 2.3 xlt that's stuck on full blast heat. I've tried to look at the vacuum lines and haven't seen any that look like they're leaking....can't be sure about that tho.

What I'm asking is, where is the actuator (or blend) door?

If I move the control knob to "anywhere", regardless of where the thermostat knob is set, I get full blast heat. The fan speed does change, but if I switch to AC, vent or anywhere, I get full blast heat. So I think it's the actuator door failing to move.

Where is that door and what does it take to get to it?

Thanks
 
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Does the air change it's location? The reason I ask, I believe your truck has a vacuum operated water control valve under the hood that turns the hot water off to the heater core. You could check to make sure it's working. If both hoses are very hot coming from and going to the heater core when the valve is supposed to be shut, I would say it's not working.
 
I'll bet that either the door actuator has failed, or the door itself is broken. It is an electric motor that is located on top of the airbox. It is a motor driven plastic gear, the arm that intersects the two breaks off, the door can no longer swing thru it's range of movement when the selector is rotated. One has to remove the motor to test it to see which is the culprit
 
Does the air change it's location? The reason I ask, I believe your truck has a vacuum operated water control valve under the hood that turns the hot water off to the heater core. You could check to make sure it's working. If both hoses are very hot coming from and going to the heater core when the valve is supposed to be shut, I would say it's not working.

Not sure what you mean by change location, but I replaced the valve your talking about a few years ago because it was leaking water. I don't think this is the issue as I've got plenty of heat....but I'll look. I thought it opened to allow hot water to go in the core, but I think it's the blend door.

I'll bet that either the door actuator has failed, or the door itself is broken. It is an electric motor that is located on top of the airbox. It is a motor driven plastic gear, the arm that intersects the two breaks off, the door can no longer swing thru it's range of movement when the selector is rotated. One has to remove the motor to test it to see which is the culprit

I think this is most likely, or something in this area, but what "airbox" are you referring to and where is it? My manual has almost no info on this.

Thanks
 
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A good article:

"Another reported fail symptom is a clicking sound coming from behind the glove box."

I always thought it was leaves had gotten in somehow.
I don't really want to do a "nail" fix, but have to wonder if these parts are available? I'll have to pull the glove box and look first.
 
IIRC you can still get the parts to do the full repair. It's just a lot more labor intensive than the alternative. I've not had to go down either road just yet, so I can't give any direct feedback.
 
I've got to finish putting my interior trim back together today first, then I'll pull the glove box and have a look.
 
Not sure what you mean by change location, but I replaced the valve your talking about a few years ago because it was leaking water. I don't think this is the issue as I've got plenty of heat....but I'll look. I thought it opened to allow hot water to go in the core, but I think it's the blend door.



I think this is most likely, or something in this area, but what "airbox" are you referring to and where is it? My manual has almost no info on this.

Thanks
I'll rephrase.......HVAC box, open the glovebox door, swing it down all the way (release the stops), one can see the motor on top of the airbox at the rear. It's a tight squeeze in there to get the screws out, if after you get it out & test it the motor still moves the arm then the door has broken the plastic fitting at the top of it. Dorman makes a replacement kit for this, to get the old door out & the new one in one cuts out the bottom of the airbox according to the template provided. Instructions are straight forward, there's no other way to get the new door in there outside of removing the entire dashboard, then removing the HVAC box from the firewall. (not a nice job)
 
I'll rephrase.......HVAC box, open the glovebox door, swing it down all the way (release the stops), one can see the motor on top of the airbox at the rear. It's a tight squeeze in there to get the screws out, if after you get it out & test it the motor still moves the arm then the door has broken the plastic fitting at the top of it. Dorman makes a replacement kit for this, to get the old door out & the new one in one cuts out the bottom of the airbox according to the template provided. Instructions are straight forward, there's no other way to get the new door in there outside of removing the entire dashboard, then removing the HVAC box from the firewall. (not a nice job)

I'll look either later today or tomorrow in the morning when it's cooler....still putting the inside trim back in from my transmission removal. Yeah, there's no way I'm going to pull the dashboard out. I'll look for the Dorman Kit.
 
My blend door actuator failed a few years ago and it was also stuck on full heat. Good thing it was winter, but even then, a single cab is quick to warmup so it became a sauna in there and if I lowered the fan, windows fogged up.

I hope for you it's also the actuator and not the door itself, as the door seems pretty hard to get to.
 
Not sure what you mean by change location,

Does it change from “vent”, “floor”, “defrost” when that knob is moved?

I had dislocated the part that attached to the thermostat on a mustang of mine one time, changing the head unit. I got stuck with full blast heat, but everything else functioned normally.
 
Yes, its called the Blend Door Actuator, Temp Knob controls this electric motor, 1995 and up Ranger

It was a common part to fail on Fords in general, so they still make them

Yes, you can see it on top of the "air box" with glove box folded down all the way


If you select MAX AC that should shut off coolant flow thru Heater core via that valve in the engine bay
Then wait a minute and air should start to get cooler, there will be residual heat in the heater core, but with flow cut off it should cool down
If not then that valve is not working like it should
 
I did change the control knob, and anything other than off seemed the same blast of very hot, including max ac, but I didn't spend but a very short period of time trying (a few seconds)...way to hot. Ive always been driving when I checked.

I CAN try max heat again, for a couple minutes, or does it take longer?

...I have many times heard the ticking sound on and off for several years....I thought it was leaves or something that got inside. Usually if I turned it on full fan, it would stop after a bit.
 
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Just turn on MAX AC after you start the engine when coolant is cold, just turn Fan speed down
Heater core should never heat up
 

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