HVAC mode blend door actuator not working properly

[bdbull]

2010 Avalanche - I can't get the mode on my heat/ac to change anymore. No matter where I set it (feet, defrost, upper vents) it doesn't really change. I got down and looked at the blend door actuator and think it's malfunctioning. When looking at it while changing the mode, I can see it turn, but it doesn't hit every "stop." There are tick marks on the actuator which I assume are for the specific modes. However, it doesn't make it all the way through all of the tick marks. Anyone know if it's supposed to or can get down and take a look at yours while changing modes?

 

[Tahoe_SSV]

Which actuator are you looking at? I'm trying to figure out which one I need to replace in my 09 Tahoe LS.

 

[bdbull]

It's on the driver side right behind the center console. You practically have to lay upside down by the pedals to see it. Mine doesn't, but it might have a cover over it. I can't quite remember and I've done so much work down there on my truck I may be missing some trim pieces.

 

[West 1]

My 2008 Suburban LTZ has this issue right now. I replaced the actuator and had it out about 8 times now, the lever with the teeth on it does move freely and will adjust from defrost to vent, the second lever turned by the mode door wheel? The large wheel the actuator connects to on install will not move the second lever that is well above the actuator and only touched by the slot in the mode door wheel. That second lever is stuck on mine and will not move, this keeps air from getting to the floor vents. Because it is stuck it also makes the actuator move to the defrost mode and stick there. I mistakenly replaced the module in the center console, no help, replaced the actuator 2 times before finding the second lever up above that is stuck causing this issue. I will report back when I find the solution or I will praise the helper that directs me to a solution! Thanks, first post on this forum but I turn wrenches all the time and I am active on other forums.

 

[swathdiver]

My 2008 Suburban LTZ has this issue right now. I replaced the actuator and had it out about 8 times now, the lever with the teeth on it does move freely and will adjust from defrost to vent, the second lever turned by the mode door wheel? The large wheel the actuator connects to on install will not move the second lever that is well above the actuator and only touched by the slot in the mode door wheel. That second lever is stuck on mine and will not move, this keeps air from getting to the floor vents. Because it is stuck it also makes the actuator move to the defrost mode and stick there. I mistakenly replaced the module in the center console, no help, replaced the actuator 2 times before finding the second lever up above that is stuck causing this issue. I will report back when I find the solution or I will praise the helper that directs me to a solution! Thanks, first post on this forum but I turn wrenches all the time and I am active on other forums.

You have to calibrate the system after actuator replacement and I've never been successful doing the manual version in this generation, it has always taken the Tech-2. A Tech-2 can talk to the BCM and give you the HVAC codes, if your controller is kaput, there's no way to know unless you can see the codes.

 

[West 1]

I have a Launch scan tool that can calibrate, I have done that to no avail. I found there are two levers moved by this actuator and wheel. One larger lever has teeth on it and moves freely. The other smaller lever only about 1 1/4" long and located above and to the right of the larger lever is not working properly. It is supposed to be able to rotate about 1", mine only moves 1/2". I think something is stuck inside the ductwork blocking the door this lever moves. I am working to find out how to get inside that duct to clear it.

 

[West 1]

When the actuator rotates it moves till it hits resistance and stops. Unfortunately for me mine stops well before it moves into the vent or floor heat positions. It is stuck on Defrost.
The stuck vent lever stops the actuator early.

 

[Doubeleive]

When the actuator rotates it moves till it hits resistance and stops. Unfortunately for me mine stops well before it moves into the vent or floor heat positions. It is stuck on Defrost.
The stuck vent lever stops the actuator early.

could be a broken door, you will probably have to pull it off and manually check if the door moves properly or not

 

[swathdiver]

I have a Launch scan tool that can calibrate, I have done that to no avail. I found there are two levers moved by this actuator and wheel. One larger lever has teeth on it and moves freely. The other smaller lever only about 1 1/4" long and located above and to the right of the larger lever is not working properly. It is supposed to be able to rotate about 1", mine only moves 1/2". I think something is stuck inside the ductwork blocking the door this lever moves. I am working to find out how to get inside that duct to clear it.

You have to put the dash in service mode, which means taking it apart to move it back on the passenger side to access the hvac so you can remove the whole thing. Good time to replace the evaporator and heater core.

SouthMain Auto on Youtube recently did a video about fixing the travel on the mode actuator to account for the foam insulation falling away.

 

[West 1]

I have seen the South Main Video, that guy is tops on the Youtube channel in my opinion. I have not found any instructions on fixing that upper vent control, I suspect something dropped into it and is blocking it. It moves and stops solid both directions but does not move enough. Thanks for the tips.

I am thinking the only access is by removing the entire dash board??? I hope not because this rig has a Dashskin installed and I don't know if it can come out without destroying it since they are glued in.

 

[West 1]

Dash is 100% removed, still no access to that lever for the Mode Actuator. Reaching down in all the vents can't quite reach the mode door that is affected. It still feels like something solid has dropped in there and it partially blocking movement.

 

[Fless]

Tried a mirror and a light to see if you can tell what's going on? Inspection camera?

 

[West 1]

Dash is now removed, dashskin came out in one good piece but took about an hour or more to get it loose and out. Even with the dash out I have yet to discover why the second mode lever will not move more than 1/2 inch causing the actuator to stop working. Can't find any others that bumped into this specific issue.
I have used mirrors, I have a 3' long flex line with a grabber at one end, I have used wire, my arms so far nothing found stuck or bad. No loose insulation like I have seen in other videos.

 

[Doubeleive]

I have seen the South Main Video, that guy is tops on the Youtube channel in my opinion. I have not found any instructions on fixing that upper vent control, I suspect something dropped into it and is blocking it. It moves and stops solid both directions but does not move enough. Thanks for the tips.

I am thinking the only access is by removing the entire dash board??? I hope not because this rig has a Dashskin installed and I don't know if it can come out without destroying it since they are glued in.

cluster has to come out and I think those covers prevent that

 

[Doubeleive]

Dash is now removed, dashskin came out in one good piece but took about an hour or more to get it loose and out. Even with the dash out I have yet to discover why the second mode lever will not move more than 1/2 inch causing the actuator to stop working. Can't find any others that bumped into this specific issue.
I have used mirrors, I have a 3' long flex line with a grabber at one end, I have used wire, my arms so far nothing found stuck or bad. No loose insulation like I have seen in other videos.

drill a hole and stick a camera in there the hole can be sealed back up later

 

[West 1]

OK, Update for today! Found the issue finally. With the dash out I was able to lift the top of the defrost vent up from the dash a little which gave some visibility down through the windshield of the defrost duct door. I did not see anything but realized I could snake a hose down there attached to my shop vac and vacuum the area out. I did this blind but heard something come up my hose. Checked the Mode actuator levers and both now worked perfectly. The small piece of plastic found was from the Old Dashboard. When I bought the truck the dash was broken pretty bad. I plastic welded it back together and put a Dash skin cover on it. It turned out very nice looking but removing the dash skin takes a lot of effort. I still need to put the entire truck back together but it all tested well and all vents appear to work as intended. The upper small mode door lever now moves right at 1" as it was supposed to.

FYI: after full dash removal which included disconnecting the battery to remove the front air bag I hooked up the power after the dash was installed and all the vents worked perfectly, I did do the normal, first put the car in AUTO mode, then turn the key to off, turn the key to ON or RUN position for 2 minutes, turn key off for 10-20 seconds and then turn the key on. Everything working normally. I never started the car for this procedure because I had my battery charger hooked up and running on a 25 amp charge. If I did not have the battery charger hooked up I would have started the engine. Modern cars draw a huge number amps with the key on and engine not running. If the system detects low voltage it puts you into electrical problems on the computer as it senses low voltage while it resets everything. So either use a good battery charger or as first instructed start the engine before doing this procedure to re calibrate the actuators. Hope this helps.

This Suburban had the JVC Radio upgrade added, what a very nice unit, has Apple CarPlay, integrates fully with your Iphone with zero effort, has the DVD player, NAV and an amazing amount of options. Like having a Ipad in your dash. I am not a stereo system guy but this is so much nicer than the OEM versions from that time.