[SOLVED] HELP! Think i messed up big time.

[white yukon]

Hey all,

So i had the bright idea of switching out the door actuator on the drivers side of a 2015 yukon. Did the typical trouble shooting and pointed to that as the issue. So when i removed the actuator being the curious person i am i grabbed the shaft to rotate by hand. Just checking to make sure the door wasn't stuck. Well, that was the fateful downfall. When turning by hand/fingers the cam seemed to move a skosh then seemed to lock up. Naturally i thought uh oh, door is stuck.

Well ended up attempting to remove the cam gear between the actuator and hvac box. As some of you may know it is a bit more complex than just a shaft with a door attached to it. Turns out i removed the whole cam assembly, off the hvac box. BIG problem. Have come to discover too late that this is a PITA to reattach. There is little to no room to maneuver the cam assembly back into place and i am afraid there is metal structure in the way which may force me to removed a bunch of stuff i don't want to.

Went searching online for tutorials or perhaps videos of people working in this area to potentially give me a better idea as to how to correct this issue. Not having much luck, well any really. Out of ideas other than removing the whole dash and not even sure that would provide access to reassemble. Might have to remove the whole hvac which is crushing for me.

Hoping someone, anyone, on here either made the same mistake and figured out a better fix than i currently fear is in front of me; or perhaps someone knows of someone who can shed some light as to how to maneuver the cam gear assembly back onto the hvac box without removal.

Any and all advise, or comments, appreciated.

 

[Tahoe14]

@Doubeleive, @Fless, @OR VietVet, @swathdiver

 

[OR VietVet]

I am a GMT800 guy and to tell you the truth, I have no idea how a driver's door actuator and an HVAC unit cross paths.

My landlord has a 2018 Suburban and I hope I never have to dig in to his to find out.

Good luck.

 

[Fless]

No clue here, either; never been near one.

 

[Doubeleive]

Hey all,

So i had the bright idea of switching out the door actuator on the drivers side of a 2015 yukon. Did the typical trouble shooting and pointed to that as the issue. So when i removed the actuator being the curious person i am i grabbed the shaft to rotate by hand. Just checking to make sure the door wasn't stuck. Well, that was the fateful downfall. When turning by hand/fingers the cam seemed to move a skosh then seemed to lock up. Naturally i thought uh oh, door is stuck.

Well ended up attempting to remove the cam gear between the actuator and hvac box. As some of you may know it is a bit more complex than just a shaft with a door attached to it. Turns out i removed the whole cam assembly, off the hvac box. BIG problem. Have come to discover too late that this is a PITA to reattach. There is little to no room to maneuver the cam assembly back into place and i am afraid there is metal structure in the way which may force me to removed a bunch of stuff i don't want to.

Went searching online for tutorials or perhaps videos of people working in this area to potentially give me a better idea as to how to correct this issue. Not having much luck, well any really. Out of ideas other than removing the whole dash and not even sure that would provide access to reassemble. Might have to remove the whole hvac which is crushing for me.

Hoping someone, anyone, on here either made the same mistake and figured out a better fix than i currently fear is in front of me; or perhaps someone knows of someone who can shed some light as to how to maneuver the cam gear assembly back onto the hvac box without removal.

Any and all advise, or comments, appreciated.

I have not had the opportunity to do the up/down actuator for the driver's side but theoretically you could adjust the actuator as needed to fit everything back together. No idea if this might work but you might be able to wrap a string around the door spindle and turn it to fit the actuator back into place then release the string. Not sure if that makes any sense either. Pictures might help so we can see what you are up against

 

[Doubeleive]

I am a GMT800 guy and to tell you the truth, I have no idea how a driver's door actuator and an HVAC unit cross paths.

My landlord has a 2018 Suburban and I hope I never have to dig in to his to find out.

Good luck.

HVAC actuator driver's side up/down, not the actual vehicle door

 

[OR VietVet]

HVAC actuator driver's side up/down, not the actual vehicle door

But he said "door" actuator and I should have guessed he meant blend door, as I read further. If the OP would have been "slightly clearer" on the explanation details, I would have had to still say, "Heck, I dunno".

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, as I am not familiar with your truck's model year, but other members of this Forum much more knowledgeable than me in this area will chime in.

 

[white yukon]

Thanks to all who took an interest. Hopefully i can clear up some stuff and leave some knowledge for future community members should they find themselves in the same bind i was in.

Yes, i should have said blend door. Thought i did but apparently not.

So long story short. Was sent on a wild goose chase for a no cold a/c issue. Ended up at the mode actuator and the end of the hvac box. The one that is on the driver side up behind the inverter box. Turns up being on the end of the hvac box just for knowledge sake. So if any of you have been up there you noticed the actuator sits on a cam gear that operates several levers. When taking out actuator i removed the can gear assembly as well. Thought i felt some binding so wanted to see if internal blend door(s) was the issue.

What i didn't see were the other 2 arms buried deep up under the dash and behind a bunch of mainly metal structure. In place it is impossible to get the arms reattached by hand which is why i was worried i would need to remove the whole dash to gain access. Well, by chance, ended up thinking why don't i see if there is any access behind everything in the center of the dash. In looking for an access route i found that by removing the center console, and bose box, there is juuuuust enough room to squeeze a fairly long flat head screw driver behind all that metal to get everything reattached. Gonna have to get the fingers in a pinch and bind but doable.

So no, no need to remove the whole dash if you mess up like i did. Just remove center console have some patience, flash light(s), cell camera helps, and lots of patience. You may have to contort yourself in some very uncomfortable positions, but no full dash removal is required.

Again, thank you all for trying to assist. Looks like i dodge a major headache, lesson learned.



keywords evap, hvac, mode blend actuator, cam wheel, cam gear, a/c, hot air,

 

[white yukon]

I have not had the opportunity to do the up/down actuator for the driver's side but theoretically you could adjust the actuator as needed to fit everything back together. No idea if this might work but you might be able to wrap a string around the door spindle and turn it to fit the actuator back into place then release the string. Not sure if that makes any sense either. Pictures might help so we can see what you are up against

Didn't think to take pics. However, in looking for a way to resolve i came across the video below. At around the 26 to 27 minute mark it showed me what i needed to see in order to confirm i could potentially resolve the matter without full removal of dash. Thought some of it might have to be done blind, but able to get in just the right positions to see what is needed and utilize tools to effectuate the reassembly.

Again, thank for the assist.

 

[white yukon]

Diggin up an old post in the hopes some folks that have been through this before may be able to provide some suggestions or feedback.

Got the whole hvac system back together. HOWEVER, since have noticed lower/slower air flow out the vents and seeing condensate on the windshield right where the defrost vent is(low center) when the A/C is on.

So here is the million dollar question, can the mode actuator be reprogrammed to fully close the defrost mode door so airflow fully comes out the actual front vents? Have tried the fuse reset and pull battery reset as well with no luck.

Trying to avoid crawling back under the dash to try to wrestle the actuation cam and actuator.

 

[JoeBlobs]

So here is the million dollar question, can the mode actuator be reprogrammed to fully close the defrost mode door so airflow fully comes out the actual front vents? Have tried the fuse reset and pull battery reset as well with no luck.

Trying to avoid drawling back under the dash to try to wrestle the actuation cam and actuator.

I know on the previous gen there is the option to do an HVAC actuator relearn with a Tech2. Sounds like that could help you, but I'm not familiar with that gen truck or how to go about it.

 

[white yukon]

I know on the previous gen there is the option to do an HVAC actuator relearn with a Tech2. Sounds like that could help you, but I'm not familiar with that gen truck or how to go about it.

When bouncing around this site i seemed to get the sense this is possible from previous and somewhat similar issues people had worked through. Was just hoping to find a definitive answer so i don't make the mistake of paying a tech to do a relearn/reset through the scanner only to find out they couldn't actually accomplish the desired result.

Really do not want to go through the hassle of pulling everything back out and trying to get the hvac mode cam back in the properly sealed position and trying to align that with the actuator itself. That was the issue last time as the cam's shaft was just barely misaligned from the actuator. Since i didn't want to force anything, for fear of breaking something, i got the bright idea of rotating the actuator receiver shaft to align with the male side of the cam gear.(Did it electronically, not manually forcing it) Thinking only 1-2mm wouldn't be a big deal and could do a reset afterward if need be. Turns out "need be" was needed, but didn't accomplish what i thought it would. The "dumb" resets didn't work for this model/instance. Thus leaving the options of manually fixing it, or hoping there is enough adjustment range in the actuator to make those minute adjustments for full range sweep relearn.

If anybody else has any other suggestions i may not have thought of, or need clarification on the problem so as to better understand so assistance can be provided, just let me know. Try to think through things thoroughly but sometimes those that have traveled the path before might know better or have wisdom to share.

EDIT: just to think through this a bit more. Lets presume the mode actuator is failing to close the defrost door fully due to a hard stop. Seems like this means going under the dash again is required as no amount of resetting or programming is going to get the internal flap/door to shut.
When reinserting the mode cam was not able to tell if it was reinstalled correctly. (Sits at the end of the hvac box almost directly above the gas pedal, offset toward center consol ) Didn't seem to have any binding and all attached levers to cam moved freely. So can't quite figure out how it could be possible to install the cam gear improperly if everything else worked perfectly. None the less, when went to put the actuator back on the cam gear it was off by just a hair.(actuator mating shaft was never moved when removed from cam gear) Didn't want to break anything so electronically roated the actuator shaft(1-2mm) to align with cam gear shaft.
Ever since, defrost door hasn't fully closed. So is it possible there is more sweep to get to the hard stop of the defrost door? Or perhaps the cam gear is fully rotating until it hits a different internal stop? By that i mean since other door levers are attached to the cam gear maybe the cam gear itself is being stopped by another door attached already at its own full stop positio, thereby not allowing the cam gear to get to true full stop via the defrost door? Basically a false sweep stop by way of another attached mode door to the cam gear assembly.
Presuming this could by a possibility would carefully removing all other attached doors via their levers, then running a dumb reset to hopfully allow the cam gear to be able to make a full mechanical sweep on its own, potentially resolve the issue? If i am wrong please correct me but seems the defrost mode door is in some way a driect attachment to the cam gear. Yes, its moved by a lever but is directly attached to cam gear where as others rely of the fulcrum of levers/rods attched to the lever of the defrost lever, iirc. Potential issue i see here would be if the process is completed and possibly succesful, might one or more of the mode door levers no longer align, or reach, the neccessary adjoining link in the chain so to speak?