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-   -   Reindexing HVAC actuators.... (https://www.corvetteforum.com/forums/c5-tech/1465931-reindexing-hvac-actuators.html)

JR_VETTE 08-07-2006 11:00 PM

Reindexing HVAC actuators....
 
After battling B0441 and B0361 HVAC codes off and on for several years :willy: , I finally decided to do something about it. After searching the helpful CF.com, I stumbled upon a thread where forum member YO-EL :thumbs: responded to someone that was having the same problem that the Actuator simply needed to be reindexed. Since then, I have done some additional research, and have performed and documented reindexing the drivers side HVAC door. I see WAY too many threads here where people are getting these same codes, and other members WRONGLY tell them to add more Freon :eek: . The above codes have NOTHING at all do to with Freon!

Anyway, long story short, I created a webpage documenting my experience with the codes, how to remove, reindex and reinstall the drivers side actuator and what seemed to cause my codes to popup. For some reason, the drivers side actuator seems to be the one that always acts up. There is probably more to determining how many 'teeth' to index by, or what direction to turn the Actuator drive gear, but from others that have reindexed, 2 teeth counter-clockwise seems to be the way to go. If anybody has more information regarding this, please PM or reply to this thread.

If you need to reindex the passenger actuator, you're on your own. :D The process is probably similar, I just can't tell you which way to reindex, and how many teeth.

I thought this might help those who are running into this problem. The usual disclaimers, etc....

Dont' blast me over the page....it's a first draft, and I probably left something out in the removal instructions.

Link

Other great posts in this thread :

http://forums.corvetteforum.com/show...9&postcount=65
http://forums.corvetteforum.com/show...1&postcount=68

Other great posts on the forum (updated 2/14/2011)
http://forums.corvetteforum.com/c5-t...actuators.html
http://forums.corvetteforum.com/c5-t...-indexing.html


EDIT - 12/26/2006 - I would like to just post a little update. So far, my actuator has worked flawlessly since this post was first made. So, I know now for a fact that reindexing is a sure fix. Also, I have received a few PM's over the past few months asking various questions. I would like to state that this project is pretty time consuming. If you page through this thread, you'll see another post where someone did the passenger side actuator by pulling the dash pad. It also looks to be a nightmare. So, if you have a weak stomach for tearing your car apart, please take it to the dealer. This requires someone with patience and small hands to get into tight places. If you can't lay on your back in a ackward position for extended periods of time, you should also pass on tackling this.

Long story short, I really just want to make sure you know what you are getting yourself into if you decide to tackle reindexing/swapping the actuator.


Edit - 2/14/2011 - While I don't have a C5 any longer, I am more than happy to keep this thread updated for you guys. Just shoot me a PM if you would like me to add links to any threads.

vettezeke 08-08-2006 09:16 PM

A/C door reset
 
Great info. I had to do the same thing to my 99 left side door last year. I am sure lots of members will find it helpful.

foremaw 08-09-2006 08:13 AM

Wow, really good info. :thumbs: So many people have had this problem (your link might be a good sticky). Hope people find this before they spend a bunch of money on the wrong fix. :cheers:

byte_me 08-09-2006 08:29 AM


Originally Posted by JR_VETTE
After battling B0441 and B0361 HVAC codes off and on for several years :willy: , I finally decided to do something about it. After searching the helpful CF.com, I stumbled upon a thread where forum member YO-EL :thumbs: responded to someone that was having the same problem that the Actuator simply needed to be reindexed. Since then, I have done some additional research, and have performed and documented reindexing the drivers side HVAC door. I see WAY too many threads here where people are getting these same codes, and other members WRONGLY tell them to add more Freon :eek: . The above codes have NOTHING at all do to with Freon!

Anyway, long story short, I created a webpage documenting my experience with the codes, how to remove, reindex and reinstall the drivers side actuator and what seemed to cause my codes to popup. For some reason, the drivers side actuator seems to be the one that always acts up. There is probably more to determining how many 'teeth' to index by, or what direction to turn the Actuator drive gear, but from others that have reindexed, 2 teeth counter-clockwise seems to be the way to go. If anybody has more information regarding this, please PM or reply to this thread.

If you need to reindex the passenger actuator, you're on your own. :D The process is probably similar, I just can't tell you which way to reindex, and how many teeth.

I thought this might help those who are running into this problem. The usual disclaimers, etc....

Dont' blast me over the page....it's a first draft, and I probably left something out in the removal instructions.

Link


Excellent info! I have this issue with mine where it comes and goes...it never really blows HOT out of the drivers side...just not as cold or with the same volume...I have GMPP on my 00 still and was going to have the dealer look at it...wonder if I should attempt this on my own first...does anyone know if they replace these with newer units that are not problematic?

Thanks!:thumbs:

zozmanZ06 08-09-2006 08:44 AM

Good Fix But...
 

Originally Posted by JR_VETTE
After battling B0441 and B0361 HVAC codes off and on for several years :willy: , I finally decided to do something about it. After searching the helpful CF.com, I stumbled upon a thread where forum member YO-EL :thumbs: responded to someone that was having the same problem that the Actuator simply needed to be reindexed. Since then, I have done some additional research, and have performed and documented reindexing the drivers side HVAC door. I see WAY too many threads here where people are getting these same codes, and other members WRONGLY tell them to add more Freon :eek: . The above codes have NOTHING at all do to with Freon!

Anyway, long story short, I created a webpage documenting my experience with the codes, how to remove, reindex and reinstall the drivers side actuator and what seemed to cause my codes to popup. For some reason, the drivers side actuator seems to be the one that always acts up. There is probably more to determining how many 'teeth' to index by, or what direction to turn the Actuator drive gear, but from others that have reindexed, 2 teeth counter-clockwise seems to be the way to go. If anybody has more information regarding this, please PM or reply to this thread.

If you need to reindex the passenger actuator, you're on your own. :D The process is probably similar, I just can't tell you which way to reindex, and how many teeth.

I thought this might help those who are running into this problem. The usual disclaimers, etc....

Dont' blast me over the page....it's a first draft, and I probably left something out in the removal instructions.

Link

This is an excellent post. I'm not sure the fix is accurate, however. To acertain the real issue, we need to determine why the actuators need to be re-indexed? If, indeed, they need to be re-indexed. The HVAC actuators have plastic gears in them. Are we finding chewed teeth in the actuators similar to the headlight motors? If we do, I can understand re-indexing or replacing the gears. If not, there may be another cause unrelated to the gears. :)

Randy

red12secz28 08-09-2006 09:37 AM

My friends 97 had the same problem. It was a broken main plastic gear in the driver side actuator. I fixed it by grinding 2 flat metal washers and putting them in the resess. Then You have to modify the casing a little to accomidate for the washers. But once your done, all you have to do is clear codes with your dic. It doesn't matter where to ac door is located. When you clear the codes the actuator recalibrates itself and then positions itself.

JR_VETTE 08-09-2006 01:27 PM


Originally Posted by zozmanZ06
This is an excellent post. I'm not sure the fix is accurate, however. To acertain the real issue, we need to determine why the actuators need to be re-indexed? If, indeed, they need to be re-indexed. The HVAC actuators have plastic gears in them. Are we finding chewed teeth in the actuators similar to the headlight motors? If we do, I can understand re-indexing or replacing the gears. If not, there may be another cause unrelated to the gears. :)

Randy

Actually the root of the problem has nothing to do with the actuator itself, but the what I call 'calibration'. The link I posted has a good GM description of what is happening. Long story short, over time, flexing of the door can cause the factory specs to no longer be accurate. The only solution is to either change out the HVAC head unit to a 2001+ unit that has logic built in to compensate for those variances, OR to reindex the actuator, so the door isn't being mashed up against the stops and causing the error to occur.

Also, there are several that have complained about broken gears, etc. I think thing goes back to the root of the problem, where the actuator is trying to force the door into a position that it simply can't do.

Thanks for all the input everyone. As stated above, and on the page, it's a VERY rough draft, and a starting point. I see almost weekly posts where people are running into the same problems I had. Hopefully it will help someone out down the road. My car is still working like a champ after reindexing my drivers side actuator.

As always, every situation is going to be different. I documented what worked for me. As they say, your mileage may vary. :D

JR_VETTE 08-09-2006 01:29 PM


Originally Posted by byte_me
Excellent info! I have this issue with mine where it comes and goes...it never really blows HOT out of the drivers side...just not as cold or with the same volume...I have GMPP on my 00 still and was going to have the dealer look at it...wonder if I should attempt this on my own first...does anyone know if they replace these with newer units that are not problematic?

Thanks!:thumbs:

Take it to the dealer. You very well may end up with the better 2001+ HVAC head unit.

Then again, you might end up with a new actuator, which according to another post I saw on the forum, can't be reindexed (something about the case not having screws??)

JR_VETTE 08-09-2006 01:32 PM

Also, I once again would like to give kudo's to forum member YO-EL. Without him, I never would have even known about the reindexing.

chuckster 08-09-2006 05:23 PM


Originally Posted by JR_VETTE
After battling B0441 and B0361 HVAC codes off and on for several years :willy: , I finally decided to do something about it. After searching the helpful CF.com, I stumbled upon a thread where forum member YO-EL :thumbs: responded to someone that was having the same problem that the Actuator simply needed to be reindexed. Since then, I have done some additional research, and have performed and documented reindexing the drivers side HVAC door. I see WAY too many threads here where people are getting these same codes, and other members WRONGLY tell them to add more Freon :eek: . The above codes have NOTHING at all do to with Freon!

Anyway, long story short, I created a webpage documenting my experience with the codes, how to remove, reindex and reinstall the drivers side actuator and what seemed to cause my codes to popup. For some reason, the drivers side actuator seems to be the one that always acts up. There is probably more to determining how many 'teeth' to index by, or what direction to turn the Actuator drive gear, but from others that have reindexed, 2 teeth counter-clockwise seems to be the way to go. If anybody has more information regarding this, please PM or reply to this thread.

If you need to reindex the passenger actuator, you're on your own. :D The process is probably similar, I just can't tell you which way to reindex, and how many teeth.

I thought this might help those who are running into this problem. The usual disclaimers, etc....

Dont' blast me over the page....it's a first draft, and I probably left something out in the removal instructions.

Link

Nice page... I like it..

I think the fix though has nothing to do with indexing. At least on the motor gear side.. Those gears are not much different than the Headlight motors. They sense resistance and determine the end of travel has been made..

However if a tooth is missing or worn on the gear..It will never reach the end of travel and time out...

My guess is that by backing the gear 2 teeth counterclockwise you are giving it a fresh set of teeth to continue on..

Similar to flipping the worn gear in the headlight motor 180 degrees..:cheers:

Either way, thank for the writeup because my DAMN AC blows much colder on the Passenger side...:rolleyes: I plan to use your fix:thumbs:

byte_me 08-09-2006 05:40 PM


Originally Posted by JR_VETTE
Take it to the dealer. You very well may end up with the better 2001+ HVAC head unit.

Then again, you might end up with a new actuator, which according to another post I saw on the forum, can't be reindexed (something about the case not having screws??)


It's going in tomorrow in the AM- I told the service advisor of the code I am getting and the symptom's (they deal in a lot of vettes here) so he was aware of the actuator issue...asked me if I was throwing the B0441 code as well...suprisingly enough - I am not...only the B0361 H C codes this time...I had the battery disconnected over the weekend for my amp install and this is the only one to come back.

I will update this thread after the dealer lets me know the issue...:willy:

YO-EL 08-09-2006 05:48 PM


Originally Posted by JR_VETTE
Also, I once again would like to give kudo's to forum member YO-EL. Without him, I never would have even known about the reindexing.

Haha! Yesss! Thanks for the mention.. Glad the A/C is working..
I have been in MANY an argument over this, way back in the day here on the forum, and I STILL get pm'd & emailed about this...!

I wonder what all the guys who have been thru actuators & control heads, re-charges, etc have to say when they still get the codes??:lol:

Bottom line, if you get the B0361 & 0441 codes, INDEX THE TEETH BY TWO.. If you don't want to believe me, then lets just say you're trying to do a HIGH RPM launch on street tires!:lol:

Ellis

byte_me 08-10-2006 08:49 AM

***update***
 
Dealer called me this morning- I dropped the car off at 7:30 EST and by 8:00 EST they called to confirm that my actuator was bad. It's covered under my GMPP major guard so they are changing it as we speak. I have the GMPP with the $100 deductible so while it was in for that- one of my FOB's was out as well...$85 to replace from Fred Beans...this was also covered under my warranty so I guess I paid for the remote and got the actuator for next to nothing!:lol:

When I get the car back- I will let everyone know if it really fixed the problem...maybe they will put in an updated actuator and all my dual zone issues will be a thing of the past!

Thank god for GMPP!:smash:

JR_VETTE 08-10-2006 06:22 PM


Originally Posted by chuckster
Nice page... I like it..

I think the fix though has nothing to do with indexing. At least on the motor gear side.. Those gears are not much different than the Headlight motors. They sense resistance and determine the end of travel has been made..

However if a tooth is missing or worn on the gear..It will never reach the end of travel and time out...

My guess is that by backing the gear 2 teeth counterclockwise you are giving it a fresh set of teeth to continue on..

Similar to flipping the worn gear in the headlight motor 180 degrees..:cheers:

Either way, thank for the writeup because my DAMN AC blows much colder on the Passenger side...:rolleyes: I plan to use your fix:thumbs:

Actually, the only thing motor resistance is probably used for is determining that the door has 'hit' something. The computer actually knows the current position of the door at all times, and expects a certain number of counts.

You can't tell in this picture, but under that blue gear is a potentiometer. It's that potentiometer that determines the current position of the drive gear, which drives the door.

http://vette.the-reeds.com/actuator/...s/image025.jpg

The calibration process is 'supposed' to determine the minimum and maximum number of counts. It's when the door goes outside the expected 0-5 as a minimum and 250-255 counts as the maximum that all hell breaks loose.

Here's the C5 TSB on the situation. I'm going to include the original link with this also.


CJ2 may experience an HVAC control head that will not properly control air mix doors after a battery disconnect. The vehicle may have a temperature difference side to side and may set DTCs B0361 and/or B0441. A typical complaint may be that the right side cools down, but the left side is warm.

Recommendation/Instructions:
Air mix door mechanical linkage build variance or wear may cause a slight over travel condition of the door. Whenever battery power is interrupted from the HVAC control module, it will perform a recalibration of the actuators once reconnected. During recalibration, the HVAC control module will drive the actuators to their minimum and maximum travel extremes (5 and 250 counts). The module issues a travel command to 0 counts, but expects to see feedback slightly less as the door hits the cold stop in the case. The module will then calculate a travel range from this data and compare it to a calibrated range within the HVAC control module. If the actual travel range is not within the calibrated expected range, the actuator will be considered not calibrated and the DTC will set and the temp door bias toward warm is the DTC failure action.

An actual range below this limit suggests an obstruction (something stuck in the door limiting travel).

An actual range above this limit suggests an over travel condition (wear, damage foam seals, etc.).

The range fault code can only be detected following a check of the left air temperature actuator travel range. The left air temperature actuator travel range check can only be initiated by disrupting power to the HVAC control module (disconnecting the battery for 60 seconds) or with the scan tool.

If thorough diagnosis of the electrical system shows all electrical components to be ok, replacement of the HVAC control module with a 2001 or newer part number is required

If this has already been done, a reset/re-time the actuators internal feedback sensor to lag slightly behind the actual position can be performed. Open the actuator case and reset the output gear and sensor gear by only 1 gear tooth. This will allow a feedback of 4 counts when performing learn.
Long story short, the HVAC controller expects to see 0-5 as a minimum and 250-255 as a maximum. IF the door isn't calibrated correctly, an example might be this :

Say my door calibrated at 5-256 counts. It's that count of 256 that sets the code. 256 is where the door reaches the 'maximum' number of counts and hits the stop. Turning the drive gear gets you back into 'accepted' range of 0-5 through 250-255.

Or it could be it's traveling from 10-255 counts...once again a code is set. You get the picture.

JR_VETTE 08-10-2006 06:25 PM


Originally Posted by YO-EL
Haha! Yesss! Thanks for the mention.. Glad the A/C is working..
I have been in MANY an argument over this, way back in the day here on the forum, and I STILL get pm'd & emailed about this...!

I wonder what all the guys who have been thru actuators & control heads, re-charges, etc have to say when they still get the codes??:lol:

Bottom line, if you get the B0361 & 0441 codes, INDEX THE TEETH BY TWO.. If you don't want to believe me, then lets just say you're trying to do a HIGH RPM launch on street tires!:lol:

Ellis

You the man! I'm still driving around nice and cool! :D

Seriously, thanks for all your help via PM's, etc. :cheers:

YO-EL 08-11-2006 09:38 AM


Originally Posted by JR_VETTE
You the man! I'm still driving around nice and cool! :D

Seriously, thanks for all your help via PM's, etc. :cheers:

:thumbs:

byte_me 08-12-2006 01:31 PM

well- the dealer replaced my drivers side actuator and all is well...I get the same volume and degree of cold as I do on the passenger side...so far no codes...

Hopefully they put in an updated actuator that will work:thumbs:

Cheers- by the way, I asked the tech doing my install what he thought about adding freon to cure this...he said while that may do something, it won't correct the issue...and the issue is the door not fully opening allowing the volume\cold to go to the drivers side...its a bad actuator...I also asked him about the "index" above...and he said he was aware of this on Buick's only...

Oh well- fo rnow mine works!

chuckster 08-13-2006 08:35 PM


Originally Posted by JR_VETTE
After battling B0441 and B0361 HVAC codes off and on for several years :willy: , I finally decided to do something about it. After searching the helpful CF.com, I stumbled upon a thread where forum member YO-EL :thumbs: responded to someone that was having the same problem that the Actuator simply needed to be reindexed. Since then, I have done some additional research, and have performed and documented reindexing the drivers side HVAC door. I see WAY too many threads here where people are getting these same codes, and other members WRONGLY tell them to add more Freon :eek: . The above codes have NOTHING at all do to with Freon!

Anyway, long story short, I created a webpage documenting my experience with the codes, how to remove, reindex and reinstall the drivers side actuator and what seemed to cause my codes to popup. For some reason, the drivers side actuator seems to be the one that always acts up. There is probably more to determining how many 'teeth' to index by, or what direction to turn the Actuator drive gear, but from others that have reindexed, 2 teeth counter-clockwise seems to be the way to go. If anybody has more information regarding this, please PM or reply to this thread.

If you need to reindex the passenger actuator, you're on your own. :D The process is probably similar, I just can't tell you which way to reindex, and how many teeth.

I thought this might help those who are running into this problem. The usual disclaimers, etc....

Dont' blast me over the page....it's a first draft, and I probably left something out in the removal instructions.

Link

I have a question.. I have the problem with the Driver Side being warmer than the PAssenger...

I do not show any HVAC codes.. Never have as far as I could tell.. Is it possible I can still fix it with your indexing procedure?

JR_VETTE 08-14-2006 08:08 AM


Originally Posted by chuckster
I have a question.. I have the problem with the Driver Side being warmer than the PAssenger...

I do not show any HVAC codes.. Never have as far as I could tell.. Is it possible I can still fix it with your indexing procedure?

Did you check the freon? If there are no codes, I would say your actuators are probably working as they should. I saw another thread where someone had the same problem as you (no codes, but warmer air on the drivers side), and adding freon did seem to help. I would check the level (let idle with A/C at MAX for at least 2 minutes, and then check the level).

chuckster 08-14-2006 08:33 AM


Originally Posted by JR_VETTE
Did you check the freon? If there are no codes, I would say your actuators are probably working as they should. I saw another thread where someone had the same problem as you (no codes, but warmer air on the drivers side), and adding freon did seem to help. I would check the level (let idle with A/C at MAX for at least 2 minutes, and then check the level).

I actually added some more on time.. but the Freon was fine... I even had to bleed a little out as the pressure was too high.. :(

IT seems to get better the longer I drive.. after 10 minutes of highway driving the difference is still there but not anyway near as much and when I first turn it on..


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