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-   -   Blend Door Actuator...How do I know which one is bad? (http://www.impalaforums.com/mechanical-and-electrical-problems/376513-blend-door-actuator-how-do-i-know-which-one-is-bad.html)

gharden2911 07-01-2013 08:11 PM

Blend Door Actuator...How do I know which one is bad?
 
I have an 8th Gen that is making the dreadful knocking noise when you adjust the temp of the A/C. I've searched and found the fix but my question is how do I know which actuator to replace. The noise is coming from behind the passenger side dash or behind the glove box. I can post a video tomorrow if anyone is interested. I would like to do the repair this weekend.

gharden2911 07-02-2013 08:06 AM

My guess is no one that's viewed this topic knows. :)

plano-doug 07-02-2013 09:57 AM

Quote:

Originally Posted by gharden2911 (Post 754089)
I have an 8th Gen that is making the dreadful knocking noise when you adjust the temp of the A/C. I've searched and found the fix but my question is how do I know which actuator to replace. The noise is coming from behind the passenger side dash or behind the glove box. I can post a video tomorrow if anyone is interested. I would like to do the repair this weekend.

Since changing the temperature causes the noise, then it is one of the blend door actuators and not the mode actuator nor the recirculate actuator. Assuming you have dual hot/cold controls, you want to change the blend door actuator on the passenger side.

This video shows where all four actuators are located. It gets to the passenger side about the 4:44 mark. HTH. Doug .


.

gharden2911 07-02-2013 01:03 PM

Hey thanks alot Doug. I thought they all were blend door actuators. Didn't know they controlled different things. Yes it's definitely on the passanger side behind the glove box.

plano-doug 07-02-2013 01:40 PM

Quote:

Originally Posted by gharden2911 (Post 755874)
Hey thanks alot Doug. I thought they all were blend door actuators. Didn't know they controlled different things. Yes it's definitely on the passanger side behind the glove box.

To be clear, both blend door actuators and the recirc actuator use the same part number.

Try these:
ACDELCO Part # 1574122 {#22754988}
ACDelco # 15-73517 (aka 1573517 )
GM# 15844096

I think the top one is the newest. I've bought a couple of the 1573517's and used them on my 07 Impala. These are about 25 bucks (plus shipping) from rockauto.com .

Doug

.

gharden2911 07-02-2013 02:27 PM

Quote:

Originally Posted by plano-doug (Post 755914)
To be clear, both blend door actuators and the recirc actuator use the same part number.

Try these:
ACDELCO Part # 1574122 {#22754988}
ACDelco # 15-73517 (aka 1573517 )
GM# 15844096

I think the top one is the newest. I've bought a couple of the 1573517's and used them on my 07 Impala. These are about 25 bucks (plus shipping) from rockauto.com .

Doug

.

That's exactly what I needed to know. I'm getting ready to order one now.:ok3:

Fitzgerald170 08-06-2013 06:30 PM

I just had my two front tires replaced, and then I turned on my A/C before I changed the air to recirculation I heard the dreaded clicking/knocking noise. I located the click to the upper right actuator, behind the glovebox which I believe to be the recirc actuator.

My question is, will this be difficult to replace? I have a 2010 Impala LT. I ordered the part and it should be here next week is that long? Will further driving cause more damage? I also read another post that states to unplug recirc motor until I replace the broken one?

plano-doug 08-06-2013 09:10 PM

Quote:

Originally Posted by Fitzgerald170 (Post 830034)
My question is, will this be difficult to replace? Will further driving cause more damage? I also read another post that states to unplug recirc motor until I replace the broken one?

Not that difficult. See the video embedded herein.

The only damage will be to the gears in the actuator that's already broken. So no worry.

Yes, if you can get up in there and disconnect it, that will keep it from annoying the holy pi$$ out of you http://www.impalaforums.com/images/icons/icon7.gif

Doug

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Fitzgerald170 08-06-2013 09:17 PM

Haha thanks Doug-
One last set of questions lol (as you can I see i am new here)... I read on another site that the actuators need to be calibrated is this true?
Also, do you need to disconnect and then reconnect the battery? Or can I just install the new actuator and call it day?

Thanks again Doug for all your help

plano-doug 08-07-2013 10:20 AM

Quote:

Originally Posted by Fitzgerald170 (Post 830362)
Haha thanks Doug-
One last set of questions lol (as you can I see i am new here)... I read on another site that the actuators need to be calibrated is this true?
Also, do you need to disconnect and then reconnect the battery? Or can I just install the new actuator and call it day?

Thanks again Doug for all your help

Hi, Fitz,

I don't really think you need to do anything to calibrate them. As best I can tell, they do that themselves. In fact, the cal process is part of what you're hearing when the clicking is happening.

Yes, it wouldn't hurt to disconnect the battery while you're working on it. That's pretty much SOP nowadays.

FWIW, the way these actuators work is similar to how the auto-down feature works on the driver's widow. There is a small microcontroller in the window switch. In the auto-down mode, it monitors the current in the window motor while keeping the relay closed powering the motor. When the window is all the way down, its motor current will jump due to the motor being stalled. The micro sees that and opens the relay thus turning off the motor.

In the actuator, the micro in the heat/AC controls drives the motor one way until it stalls, then drives it the other way and measures the elapsed time for the actuator to move lock-to-lock. Knowing the lock-to-lock time, the micro knows how long to drive the motor to get the actuator to some fractional position between the lock points.

The process works this way to reduce cost. In the old days, there would have been sensors on the actuator which detected when it was at the ends of its travel. The sensors and wires added lots of cost. But by simply monitoring the current going to the motor, we can tell when it has stalled, so no sensors are needed. This is sort of an example of open loop control versus closed loop control.

The clicking you hear is due to the gears being stripped. The micro is driving the motor waiting for the current to jump, but it never does because the stripped gears don't stall the motor. After a while, the process times out and the clicking stops. (The software gets tired of trying and gives up.) The key point is that the clicking is actually part of the on-going self-cal done by the micro in the heat/AC controls.

Doug

.

phirleman 08-17-2013 11:19 AM

I'm having the same issue only the clicking is behind the steering wheel
 
Where is this one located? And how hard to r/r it.

:dunno:


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