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Discussion Starter · #1 ·
Posting here hoping for some more input!

I know this is a common problem.

my HVAC is malfunctioning, its the actuator out of range error. mine's on the passenger's side. when I drive the car all is well for about 10 minutes then cold air starts pouring in on the passenger's side. I'm getting codes:

B0441 H
B0446 H C

indicating passenger's side HVAC actuator out of range.

I got into it and rotated the main gear clockwise two teeth. I got some help and did some research. CCW seems to fix the driver's actuators which was the only info I could find, so I guessed and went CW on the passenger's side.

all was working perfectly for the last 6 weeks, then today on the way to work it failed again, exact same symptoms, same codes.

looking for any and all help, what do I do now? I can get back to the actuator that's not a big deal. but what do I do once I'm in there? does it need replaced? should I rotate 4 teeth CCW (net of 2 CCW) just like on the driver's side? or is the newer 04 HVAC head unit which is supposed to be more tolerant of out of range conditions my best bet? for anyone who's dealt with this before, please help!
 

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That's not a problem I've ever encountered. I'll pm those that should know and see if we can't get some help here. :thumbsup:
 

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Okay, have you tried the most obvious fix, re-indexing or calibrating the actuators? That is the first thing that you should have tried.
 

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Discussion Starter · #6 ·
Okay, have you tried the most obvious fix, re-indexing or calibrating the actuators? That is the first thing that you should have tried.
yes. did the fuse pull as well as the clear codes and allow recalibration thing. no fix.
then i pulled the actuator out and reindexed the gear 2 teeth clockwise. that fixed it for about 6 weeks. now the problem is back.
 

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yes. did the fuse pull as well as the clear codes and allow recalibration thing. no fix.
then i pulled the actuator out and reindexed the gear 2 teeth clockwise. that fixed it for about 6 weeks. now the problem is back.
Did you do the reindexing per the service manual or just pull the fuse?
 

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Discussion Starter · #8 ·
Did you do the reindexing per the service manual or just pull the fuse?
ah! i wasnt aware gm had a different procedure for that. i pulled the fuse and reset codes. thats all. what is the service manuals procedure? i have the manual. is it easy to find? ill try it tonight..
 

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Yes, there is a specific way to do it per the service manual. I've posted the instruction on this forum if you can't find them in the service manual.
 

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Discussion Starter · #10 ·
Yes, there is a specific way to do it per the service manual. I've posted the instruction on this forum if you can't find them in the service manual.
Hey, I found the diagnostic chart for air temp control inoperative passenger (CJ2) but it didn't mention a recalibration procedure. would you happen to have a link?
 

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Discussion Starter · #12 ·
This thread, and post #8 has the instructions.
Thanks Junkman! it sounds simple enough. I tried that the last time but it didn't fix the issue. actually last time I left the fuse out all weekend. I have it out now we'll see what happens. after I turned the gear it worked for a while, maybe the recalibration along with the gear turning will do it some good.
 

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Thanks Junkman! it sounds simple enough. I tried that the last time but it didn't fix the issue. actually last time I left the fuse out all weekend. I have it out now we'll see what happens. after I turned the gear it worked for a while, maybe the recalibration along with the gear turning will do it some good.
Or, maybe the actuator is bad. They do go bad you know. I had this problem a few times and the recalibration fixed it. Then I found out that spinning the temperature knob too fast can throw the actuators off also. I then figured out that if I set the temperature to its lowest point, turned the car off and back on again, set the temperature to its highest point and repeated the on/off of of the engine, it would sometime correct itself. It was as if I was showing the actuators their high low points. I bet your mistake is turning that knob too fast. That causes a lot of different problems with the HVAC. Here's a link to that TSB.

Disconnecting the battery improperly is another thing that causes havoc in multiple systems.
 

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Discussion Starter · #14 ·
Or, maybe the actuator is bad. They do go bad you know. I had this problem a few times and the recalibration fixed it. Then I found out that spinning the temperature knob too fast can throw the actuators off also. I then figured out that if I set the temperature to its lowest point, turned the car off and back on again, set the temperature to its highest point and repeated the on/off of of the engine, it would sometime correct itself. It was as if I was showing the actuators their high low points. I bet your mistake is turning that knob too fast. That causes a lot of different problems with the HVAC. Here's a link to that TSB.

Disconnecting the battery improperly is another thing that causes havoc in multiple systems.
thanks! you're a wealth of information!

when I fixed it the first time I had the actuator out of the car.
the most common way I see these failing in pictures anyway is the large gear physically cracking. mine was in tact. once I moved the gear a couple teeth and reinstalled it I watched it operate. I could run the car with the dash pad off and rotate the knob from hot to cold and watch the shaft turn, so at least that part was working.

when this fails it does so like it did the first time. usually it works fine when I first start the car. after about 10 minutes I start to feel cold air and put my hand in front of the vent and its freezing. since this has been happening I've been checking the vent, it definitely works at first then stops. of course in the last couple of days the problem has been getting worse and I've noticed it blowing cold from the very beginning.

I noticed (if this picture works) that the "new" actuator:

has these two little depressions on the top of the case, right over where the main gear is. I suspect these might be the actuator stops that some have mentioned. if the actuator takes care of the stop position and not the door which tends to warp, maybe a new actuator would be the simplest solution?

I'll try to get the car out today and see if the fuse pull for 60 seconds made any difference.
 

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They corrected some problem with the old actuators, but I don't remember exactly what it was. Although expensive, I would say that replacing the actuator in question may be the route to go if you keep experiencing the problem. Here's a zip file that will help you determine if that is necessary. A scan tool is a must in diagnosing this problem for sure.
 

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Discussion Starter · #16 ·
No issues on the way to work today. Looks like it's better at least for now. I well see how long that lasts. If I have to pull the fuse for a minute every couple months that's no bid deal. If it needs it weekly then I guess I'll replace the actuator and see if that fixes it.
 

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Discussion Starter · #17 ·
No good. Official reindexing procedure fixed it for less than one day. Is replacing the actuator withwith one of the new "redesigned" ones the next step?

Do we know if the door position feedback counts are a li. Ear mapping from 0 to 255 as 0.0 to 5.0 volts? I could read the feedback with aa Meter and a calculator. I but I don't know if it would be accurate enough to diagnose.
 

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No good. Official reindexing procedure fixed it for less than one day. Is replacing the actuator withwith one of the new "redesigned" ones the next step?

Do we know if the door position feedback counts are a li. Ear mapping from 0 to 255 as 0.0 to 5.0 volts? I could read the feedback with aa Meter and a calculator. I but I don't know if it would be accurate enough to diagnose.
That's why I said that you would need a scan tool along with those instructions I posted to diagnose it correctly. With the cost of the actuator, I wouldn't just slap a new one in there and hope it works (although they do fail and the new ones corrected an issue with the old ones). If you don't have a scan tool but know a reputable mechanic who does have one, you could have him use the instructions I posted and diagnose it for you. That would be the proper way to find out exactly what the problem is, although you could do the actual repair yourself. That's what I would do.

I hate guessing at repairs because I don't learn what the "why" is behind the fix. Since I never plan to get rid of my car, I want to know everything that I can possibly learn about it.
 

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Discussion Starter · #19 ·
That's why I said that you would need a scan tool along with those instructions I posted to diagnose it correctly. With the cost of the actuator, I wouldn't just slap a new one in there and hope it works (although they do fail and the new ones corrected an issue with the old ones). If you don't have a scan tool but know a reputable mechanic who does have one, you could have him use the instructions I posted and diagnose it for you. That would be the proper way to find out exactly what the problem is, although you could do the actual repair yourself. That's what I would do.

I hate guessing at repairs because I don't learn what the "why" is behind the fix. Since I never plan to get rid of my car, I want to know everything that I can possibly learn about it.
I agree with you. I wish I had a Tech 2. found one forsale on amazon for the low price of $2500. some day maybe. for now...

well I think this is what I'm going to do. I'm going to pull the car apart again hopefully this weekend. I'm going to try to tap into the position signal from that actuator and the ground so I can hopefully get a good reading. if the range is linear, then the error zones should be anything less than 0.1V or over 4.9V, I'll see what information I can get. if I can get an accurate enough reading maybe I can tell which direction it is out of range, I'll figure out which way is which by taking the actuator apart, plugging it in, and rotating the potentiometer inside, then try moving the gear a tooth or two in the right direction. then just see how that goes. hopefully I can reset the codes or pull the fuse and watch the feedback signal as it calibrates and see the full range. if I can't get it to stay within the proper range, I'll replace the actuator.

even if I can, if it fails again I'll try replacing it. in either case, do you know what else fuse 18 feeds? I'm wondering if I can try to get the blend door to close and then pull the fuse so the computer can't open it again temporarily until I get a new actuator in.

its really frustrating that the engineer who designed it set it up so that if it goes out of range the failure mode is to open the door letting outside air in. if only it would close when failed, then at least my fingers wouldn't be getting numb while driving. then you'd have too much heat, which could very easily be regulated with the fan speed and opening the windows a little. but nothing I can do about that.

so that's what I plan to do, any further suggestions?
 

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None here. With the direction that you plan to go, I would say that your thinking is as good as any. I'll be curious to see what you come up with.
 
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