Air blend door actuator clicking
November 23rd, 2017, 1:10 PM
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Air blend door actuator clicking
The air blend door actuator on my 2008 Chev Impala has started clicking...the heater & front defrost are still working properly...After setting all heater & front
defrost controls in normal position, Can I unplug the power to the blend door actuator?...Will my heater & front defrost still function until I obtain a replacement
air blend door actuator?...thanks,.......update, this problem has been mentioned on these forums previously, here is the link....https://chevroletforum.com/forum/imp..........perhaps this additional info will help another member...
defrost controls in normal position, Can I unplug the power to the blend door actuator?...Will my heater & front defrost still function until I obtain a replacement
air blend door actuator?...thanks,.......update, this problem has been mentioned on these forums previously, here is the link....https://chevroletforum.com/forum/imp..........perhaps this additional info will help another member...
Last edited by Michael Walters; November 29th, 2017 at 10:11 AM. Reason: updating info
November 24th, 2017, 8:12 AM
#2
yep, unplug it. depending on whats broke, the door may or may not move.
the door may be broken...the clicking is the hvac module trying to perform a range calibration
the door may be broken...the clicking is the hvac module trying to perform a range calibration
November 29th, 2017, 10:23 AM
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Many complaints from GM owners on this air-blend-door-actuator-clicking
October 30th, 2017, 10:19 PM #1
Montana Cowboy
Hear knocking noise coming from heater
Howdy All
When I turn my ignition switch to on while starting the engine I get a steady knocking noise coming from the heater motor area. It lasts for about 20 seconds and then stops. It also does this when I turn the engine off. Anyone know what is causing this? Thank you MC.
P.S. My truck is a 1991 2500 Silverado.
Montana Cowboy
Last edited by Montana Cowboy; October 30th, 2017 at 10:22 PM.
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October 31st, 2017, 5:52 AM #2
burnhedge
It's either the blend door or the door that changes your vents. It cycles when the key is turned on/off. Very common on these trucks.
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November 1st, 2017, 4:21 AM #3
Montana Cowboy
Hear Knocking noise coming from heater
Posted By: burnhedge
It's either the blend door or the door that changes your vents. It cycles when the key is turned on/off. Very common on these trucks.
Thank you for the reply burnhedge. Is it easy to access the switch? MC
Montana Cowboy
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November 1st, 2017, 8:20 AM #4
burnhedge
I looked through some old posts and it's actually the actuator for the fresh air door that causes the noise. It's really not hurting anything but if you hate the noise and want to replace it, just pull the glove box liner out and cycle the key. Should be easy to identify which actuator it is.
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November 1st, 2017, 5:50 PM #5
Montana Cowboy
Thank you burnhedge I'll pull the liner out and see what I can find. Will get back and let everyone know what I find so others will know if they have this problem. MC
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November 14th, 2017, 4:08 AM #6
Montana Cowboy
Howdy Folks
I fixed my problem by changing the Blend Door Actuator. It was a pain where it is located on the 1991 Chevy Silverado on the passenger side. After removing the glove box I could reach in with my left hand all the way to the firewall and then using a common screwdriver in my right hand to hold pressure against the 1/4 drive ratchet to hold it in place on the screw head while I repositioned my left hand to turn the ratchet to back the screw out. This wasn't done in one try because the socket would easily come off of the screw head because there just isn't any room to work plus having arthritis in both thumbs made it difficult. This was the upper screw that was difficult. The bottom screw is easier to remove.
I couldn't get the upper screw to back all the way out and what happened by accident was I broke the structure (actuator mounting hole housing ) on the actuator after which I was able to remove the upper screw pretty easy from underneath the dash..
The new BLEND DOOR ACTUATOR is centered such that it is located half way between open and closed. I tried to move ( gently) it to the full closed position so that it would fit on the " blend door shaft " but you are not able to move it by hand and I did not want to try and force it because that would damage the actuator.
The new BLEND DOOR ACTUATOR does not give instructions on how to clock the actuator to match the shaft on the blend door itself it just says " WARNING DO NOT apply power to the actuator until it is installed onto the blend door ". There are no instructions on how to do this and I didn't know that I could move the blend door ( I did not realize / see that the blend door could be moved by hand until I had bumped it with a screw driver by accident ) by hand to match the new actuator.
Now I know that you can move the blend door by hand to match the actuator position. I had no prior experience with these and again I did not realize that the blend door could be moved by hand until I bumped it with the screwdriver. I took a chance and hooked it up to the electrical connector and turned the key to the on position and this moved the actuator shaft to the correct position that matched the shaft on the blend door itself. I got lucky that I didn't over travel the actuator.
A CAUTION is required here, as soon as you turn the key to the on position power is applied to the actuator and it begins to move which brings up the CAUTION note provided by the manufacture. The manufacture of the actuator states that " IF ACTUATED PRIOR TO INSTALLATION ON THE BLEND DOOR, IT IS POSSIBLE TO ROTATE THE OUTPUT SHAFT BEYOND THE FULL HEAT OR FULL COLD POSITION. IF THE ACTUATOR ROTATES BEYOND THE FULL HEAT OR FULL COLD POSITION INDICATED BY THE ARROWS IT WILL NOT FUNCTION PROPERLY WHEN INSTALLED ON THE VEHICLE. So be careful when / if you apply power to position the output shaft on the actuator because as soon as power is applied the shaft will begin to move.
I installed the upper screw by gluing the screw to the socket( 7MM socket) and then used a short adapter that is 1/4 drive on one end and hex head on the other end. Once I got the screw positioned ( this took a numerous attempts to get the screw in the actuator housing hole) I was able to turn it as far as I could by hand and the used a small wrench on the short extension to turn the screw the rest of the way in.
Hope this makes sense to folks especially those who have to change one. MC
Montana Cowboy
October 30th, 2017, 10:19 PM #1
Montana Cowboy
Hear knocking noise coming from heater
Howdy All
When I turn my ignition switch to on while starting the engine I get a steady knocking noise coming from the heater motor area. It lasts for about 20 seconds and then stops. It also does this when I turn the engine off. Anyone know what is causing this? Thank you MC.
P.S. My truck is a 1991 2500 Silverado.
Montana Cowboy
Last edited by Montana Cowboy; October 30th, 2017 at 10:22 PM.
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October 31st, 2017, 5:52 AM #2
burnhedge
It's either the blend door or the door that changes your vents. It cycles when the key is turned on/off. Very common on these trucks.
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November 1st, 2017, 4:21 AM #3
Montana Cowboy
Hear Knocking noise coming from heater
Posted By: burnhedge
It's either the blend door or the door that changes your vents. It cycles when the key is turned on/off. Very common on these trucks.
Thank you for the reply burnhedge. Is it easy to access the switch? MC
Montana Cowboy
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burnhedge's Avatar
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November 1st, 2017, 8:20 AM #4
burnhedge
I looked through some old posts and it's actually the actuator for the fresh air door that causes the noise. It's really not hurting anything but if you hate the noise and want to replace it, just pull the glove box liner out and cycle the key. Should be easy to identify which actuator it is.
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November 1st, 2017, 5:50 PM #5
Montana Cowboy
Thank you burnhedge I'll pull the liner out and see what I can find. Will get back and let everyone know what I find so others will know if they have this problem. MC
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November 14th, 2017, 4:08 AM #6
Montana Cowboy
Howdy Folks
I fixed my problem by changing the Blend Door Actuator. It was a pain where it is located on the 1991 Chevy Silverado on the passenger side. After removing the glove box I could reach in with my left hand all the way to the firewall and then using a common screwdriver in my right hand to hold pressure against the 1/4 drive ratchet to hold it in place on the screw head while I repositioned my left hand to turn the ratchet to back the screw out. This wasn't done in one try because the socket would easily come off of the screw head because there just isn't any room to work plus having arthritis in both thumbs made it difficult. This was the upper screw that was difficult. The bottom screw is easier to remove.
I couldn't get the upper screw to back all the way out and what happened by accident was I broke the structure (actuator mounting hole housing ) on the actuator after which I was able to remove the upper screw pretty easy from underneath the dash..
The new BLEND DOOR ACTUATOR is centered such that it is located half way between open and closed. I tried to move ( gently) it to the full closed position so that it would fit on the " blend door shaft " but you are not able to move it by hand and I did not want to try and force it because that would damage the actuator.
The new BLEND DOOR ACTUATOR does not give instructions on how to clock the actuator to match the shaft on the blend door itself it just says " WARNING DO NOT apply power to the actuator until it is installed onto the blend door ". There are no instructions on how to do this and I didn't know that I could move the blend door ( I did not realize / see that the blend door could be moved by hand until I had bumped it with a screw driver by accident ) by hand to match the new actuator.
Now I know that you can move the blend door by hand to match the actuator position. I had no prior experience with these and again I did not realize that the blend door could be moved by hand until I bumped it with the screwdriver. I took a chance and hooked it up to the electrical connector and turned the key to the on position and this moved the actuator shaft to the correct position that matched the shaft on the blend door itself. I got lucky that I didn't over travel the actuator.
A CAUTION is required here, as soon as you turn the key to the on position power is applied to the actuator and it begins to move which brings up the CAUTION note provided by the manufacture. The manufacture of the actuator states that " IF ACTUATED PRIOR TO INSTALLATION ON THE BLEND DOOR, IT IS POSSIBLE TO ROTATE THE OUTPUT SHAFT BEYOND THE FULL HEAT OR FULL COLD POSITION. IF THE ACTUATOR ROTATES BEYOND THE FULL HEAT OR FULL COLD POSITION INDICATED BY THE ARROWS IT WILL NOT FUNCTION PROPERLY WHEN INSTALLED ON THE VEHICLE. So be careful when / if you apply power to position the output shaft on the actuator because as soon as power is applied the shaft will begin to move.
I installed the upper screw by gluing the screw to the socket( 7MM socket) and then used a short adapter that is 1/4 drive on one end and hex head on the other end. Once I got the screw positioned ( this took a numerous attempts to get the screw in the actuator housing hole) I was able to turn it as far as I could by hand and the used a small wrench on the short extension to turn the screw the rest of the way in.
Hope this makes sense to folks especially those who have to change one. MC
Montana Cowboy
