air vent blower stuck on top and bottom

MoMobile

Original poster
Member
Apr 9, 2012
31
The air no longer comes out of the center (dash) vents, regardless of where I put the switch on the dash panel.

The air only comes out of the top (defrost) and lower (foot) vents.

Does this mean there is an acuator stuck or hose come loose? Any diagrams or steps on how to check it would be appreciated.

EDIT: it is a 2004 Envoy
 

meerschm

Member
Aug 26, 2012
1,079
http://gmtnation.com/f23/2002-envoy-mode-door-actuator-replacement-2787/

good place to start. (while The Roadie is still sleeping)

I get the impression the actuators are a common failure. The HVAC doors are electrically operated. Computer controlled. No vacuum hoses.

I just replaced my drivers temp actuator yesterday. Several years ago, I had a dealer replace the floor/vent actuator which was the solution to my complaint of a condition similar to yours.

My service manuals came in handy, but I almost got whiplash from the multiple references. Was like one of the paperback books my kids used to read that had the reader make choices and then turn to other pages. These babies are buried so deep in the dash you would think they are processing uranium for an ilicit weapons program. I skipped a few steps, like remove the steering column.

It sounds to me like the mode actuator may be kaput. It takes an expensive piece of software to verify this failure. There are diagnosis steps in the service manual, but they assume you have a scan tool which can read the HVAC parameters. There are also a handful of temperature sensors, as well as optical sensors on the dash that the computer uses to decide which door goes where.
 

meerschm

Member
Aug 26, 2012
1,079
Rock Auto has them too. some discounts around here someplace, or you can google em up.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
meerschm said:
My service manuals came in handy, but I almost got whiplash from the multiple references.
The GM factory service manuals are a unique resource, but when you compare them to a Honda service manual, the GM ones look like crap. They could be half as thick if they removed the "how to put it back together" sections, which contain exactly the same illustrations as the "how to take it apart" sections except the order is reversed. It's nuts. And don't get me started on their criminal INDEXING skills. If such a team of tech writers presented that product to me for review they'd be on the street in an hour.
 

MoMobile

Original poster
Member
Apr 9, 2012
31
black ice said:
I just had one replaced, it was a 90 and some change part from the dealer.
meerschm said:
Rock Auto has them too. some discounts around here someplace, or you can google em up.

Please define "one" and "them", I have no idea what I'm looking for to search or inquire at the dealer. Thanks.
 

meerschm

Member
Aug 26, 2012
1,079
MoMobile said:
No, sorry, I did not notice the link and thanks for pointing it out to me. :smile:

I will try to make it clearer from the context in future posts. it does kind of look like a title at the top of my post.
 

MoMobile

Original poster
Member
Apr 9, 2012
31
I just got the shop to do this, I didn't want to mess up the dash. It was a bit over $400 parts and labor.
 

redman

Member
Jul 15, 2013
2
Thank you all posters, without this forum I would not have been able to do this.

I have a 2006 GMC Envoy Denali. I could not get any air (hot or cold) from the dash vents, only air blowing from the defrost vents and foot vents, and the back seat vents. After hours of searching I could not find my exact car help, but it sounds like this was the mode door actuator, and the dealer wanted $875 to replace this, the dealer said they probably would have to remove the dash. I decided to try this myself. I am not sure if this is the best way to to do this, but I could find no other way on the internet (granted I did not read every single post on here, I figured reading posts for several hours and not finding anything that seemed perfect was enough research).

I was not sure which actuator this was, and I didn't find any good pictures or manuals of where they all are located, so this was a little bit of an exploratory process for me. I started pulling apart the dash, thinking how hard can this really be.

Well, after a few hours I finally had a bunch of panels and part and the dash loose, but I could not get it over the steer wheel. I could not find good instruction on steering wheel removal for my car, until I found this site by accident Wood Grain Steering Wheel Manufacturer Accessory Chevy GMC OEM Silverado Tahoe Avalanche Suburban Sierra Yukon H2 Hummer in Burl Walnut Rosewood Black Cherry (for steering wheel upgrade kits), this webiste had great instruction on steering wheel removal and help me find out I need a special GM Puller (it has shafts with hooks instead of the normal threaded bolts), that most of the auto parts places did not have, or the workers did not know I really needed a special puller. Once the dash was off, I finally was able to see (and feel the actuator actually making the noise) the mode door actuator was way up in the dash on the drivers side of the center venting stack. I still could not get to the actuator (and see and barely feel it) and thought I would have to remove some of the major metal and cast structure. I decide to try and remove some of the vent ducting that was on top, and as I did, I discovered the large top vent cowl came out rather easily and revealed a relatively easy way to get to the actuator.

Once I removed the actuator (on the white label was HL 52402610 010052792A) the internal vent door swung open (this internal door was not very visible with the large venting cowl removed, revealing that I was on the right tract. I got a new actuator from a local store (Carquest had an aftermarket one in stock) and installed it. I wasn't sure about the position of the acuator and where the vent door should be so I decide to just give it a try and install it. I tested the vent system with everything still exposed and realized the actuator was not fully opening. So I removed the actuator (after disconnecting the battery again) and was actually able to reposition the actuator a little, moving it VERY slowly, and reinstalled it. Now the door would not shut fully, but at least I believe the actuator was at the end of its travel after being moved by the system. So I pull the actuator off again and reinstalled it while holding the internal vent doors in the closed position, and now this did the trick.

BTW, the bolt heads on the screws that hold that actuator would only fit in my 5.5 mm socket (I did not have standard socket that small), and I had to use a little thumbwheel ratchet since the access is still VERY tight to the actuator bolts when coming in from the top.

I reinstalled the dash, but was left with one yellow connetor that I could not find a mate for under the glovebox (see picture which is from a different car I found on this forum but looks the same), if anyone knows what this should be connector to, or it was not connected to start with (I cannot remember when I disassembled this area and I did not document my steps very well) I would be greatly appreciative. Everything seems to work fine now, at least that I have checked. So perhaps this was just not connected to start...?
 

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The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
redman said:
..(see picture which is from a different car I found on this forum but looks the same), ..
That's mine. Yellow connectors relate to the airbag system. If you reconnected the one going to the passenger side unit, and the service airbag light is off, that's probably for a side curtain airbag your truck was built without.

On the actuator location issue, I thought EVERYBODY has seen (or knows how to locate in a Google image search) this illustration I put together YEARS ago:

allactuators-orig.jpg
 

06_GATOR_VOY

Member
May 22, 2013
250
ok so how hard is this to do? also how do you know which actuator is bad? i recently installed a new battery and before that the a/c worked great but after the battery install i didnt allow the system to reclibrate as i was not aware of this since we a noob to the truck etc ive tried resetting it with the battery... going to try the fuse and see what happens. the settings on the a/c need to be off right? hopefully i can get it to reset. going to drive it home tonight without touching the controls and then in the morning see if they are reset. fingers crossed. i know i dont have the tools for this kinda job. just have the simple mechanics set.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Pull the fuse for 30 seconds. Put it back in. Then turn the ignition on but no need to start the engine. Doesn't matter what mode the controls are in when you do this, but some people prefer to set them to off before pulling the fuse. Leave everything untouched for 90 seconds. Then start the engine and test things out.

Actuators are tested functionally. The airflow mode selects dashboard versus feet vents. If you get no change when you select feet or dash vents, it's the problem. Driver's and passenger's side TEMP actuators are pretty obvious. Defrost is also obvious. Recirculate is also obvious. See the trend I'm getting at? Each of the five actuators has a purpose and a name. If they aren't doing their jobs, the thing they're named for is not happening.
 

redman

Member
Jul 15, 2013
2
06_GATOR_VOY said:
ok so how hard is this to do? also how do you know which actuator is bad? i recently installed a new battery and before that the a/c worked great but after the battery install i didnt allow the system to reclibrate as i was not aware of this since we a noob to the truck etc ive tried resetting it with the battery... going to try the fuse and see what happens. the settings on the a/c need to be off right? hopefully i can get it to reset. going to drive it home tonight without touching the controls and then in the morning see if they are reset. fingers crossed. i know i dont have the tools for this kinda job. just have the simple mechanics set.

I am pretty handy, and it took me about 10 hours total, including all the research on details when I got stuck, I guess that is why the dealership wanted to charge $875 to replace this. Until I figured out how to pull the steering wheel I was just about to give up, this was about 7 hours into it. I had to remove the steering wheel (which required a GM steering wheel puller, which was somewhat hard to find at the parts stores), and this means disconnecting and removing the steering wheel airbag, and disconnecting the passenger airbag, which many people are nervous doing. Unless you have all the proper tools, are pretty confident with this type of work, and not afraid of potentially severely injuring (or killing) yourself if you accidentally set off the airbag, then you may want to have a pro do this.

I figured out which actuator it was by finally finding all the actuators and then being able to get my finger on each one to feel which one had that knocking noise, it was pretty obvious by feel. Although, when I felt the first two actuators that are closer to the floor and easiest to see, I did feel a slight knocking, but that was a transferred feeling for the real culprit higher up in the dash. The Roadie has a very helpful diagram just a few posts prior to this one in this thread, look for that. Also, once I got the entire dash apart and was able to see the internal doors that should be moving (when testing the various blower options), but were NOT moving, I was then 100% sure which actuator it was.

I am not sure if I did the most efficient way to replace the mode door actuator. My car ('06 Envoy Denali) does have the adjustable pedals and I didn't even think of trying to remove those, perhaps I could have replaced the actuator from below, but ultimately I had a challenging enough time trying to align the gears of the actuator to the door gears (and I actually moved the door with my hand since it was accessible the way I did things by going in from the top by removing some of the top vent cowls) to help properly adjust the movement of the actuator. I could not seem to see how the calibration process works, it did not work for me. I had to remove the new actuator three times while checking the operation each time before I could get the proper operation.

Good luck!
 

06_GATOR_VOY

Member
May 22, 2013
250
so pulled the fuse waited then put back in after a minute then turned the key to the on positiin without starting the truck. waited 2 mins w/o touching anything. sounded like it ran thru everything so start up the truck n it sounds like it trys to run thru it again.....give up on this shit. take it a knocking sound from the actuators is not a good thing. have to call the dealers n get quotes......no time to pull dash
 

meerschm

Member
Aug 26, 2012
1,079
you might be able to get to it. one way to find out.

:wink:

some are buried deeper than others. I think the mode actuator can be got to the easiest, so this could be your lucky day.
 

06_GATOR_VOY

Member
May 22, 2013
250
meerschm said:
you might be able to get to it. one way to find out.

:wink:

some are buried deeper than others. I think the mode actuator can be got to the easiest, so this could be your lucky day.

lol you edited your first post.... was going to reply challenge excepted lol
 

Menthol

Member
Dec 8, 2011
177

Menthol

Member
Dec 8, 2011
177
06_GATOR_VOY said:
so had the actuator replaced n still have the problem

Exactly what is the issue?
The mode actuator directs airflow the to the directional vents, it that the same problem still?
I'm having issues with no AC on drivers side.
 

06_GATOR_VOY

Member
May 22, 2013
250
Menthol said:
Exactly what is the issue?
The mode actuator directs airflow the to the directional vents, it that the same problem still?
I'm having issues with no AC on drivers side.

having the issue of it wont blow out the front vents just the floor and defrost.
 

Menthol

Member
Dec 8, 2011
177
06_GATOR_VOY said:
having the issue of it wont blow out the front vents just the floor and defrost.

Did you try reset again, can you see it moving? did you feel the flap moving before instalation? Don't know what else to try but take it out and try again.
 

06_GATOR_VOY

Member
May 22, 2013
250
the roadie said:
Who did it? Sure they changed the right one? Didn't they guarantee their work? Did they properly recalibrate the actuator afterward?

some shop 2 hrs away lol. pretty sure they changed the right one. since it didn't work they took it back out and put the old one back in and no charge. to be honest not all sure what they did since I wasn't the one who brought the truck in and wasn't there. was relayed the info. last I heard was possible control module but haven't heard anything back......
 

06_GATOR_VOY

Member
May 22, 2013
250
so i gotta laugh.... the shop did a bunch of test etc to try and locate the problem and where do they come back to? the actuator. apparently the person working on it didnt run thru the calibration so they are sending someone out to take care of it meaning they are traveling to where the truck is to fix it etc. nothing hurt just sucks for them they wasted their time twice lol. should be fixed today with new part etc.
 

06_GATOR_VOY

Member
May 22, 2013
250
fixed... was alil less than 150 for the repair. also had the recall issue on the window switch taken care of.
 

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