2014 Denali auxiliary HVAC Temp door code B0433

[14Nali]

Hi Everyone, I’m really struggling with a rear hvac issue. The issue is that is only blows hot in rear . I’ve scanned it with a tech 2 and get code B0433. It shows symptom byte 5 and 4. I’ve cleared it and it has also shown symptom byte 2. Below is all of the thing I have tried with no luck.

Clearing the code and relearn
Replaced the actuators with OEM parts.
Swapped the actuators to verify that this is not the issue.
Checked blend door function.

On the tech 2 I can get the front hvac actuators to move in both directions, but the rear hvac actuators will not move all the way to cold or hot / floor or ceiling when I issue that command.

I’m leaning towards wiring or the hvac module.

Can anyone point me in the right direction. I can test the wiring for 12v and ground but don’t know how to test for the 5v signal. I have no ideas how to test the hvac module itself.

Thanks
David

 

[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 help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.

@swathdiver may be able to give you some troubleshooting pointers.

 

[swathdiver]

Hi Everyone, I’m really struggling with a rear hvac issue. The issue is that is only blows hot in rear . I’ve scanned it with a tech 2 and get code B0433. It shows symptom byte 5 and 4. I’ve cleared it and it has also shown symptom byte 2. Below is all of the thing I have tried with no luck.

Clearing the code and relearn
Replaced the actuators with OEM parts.
Swapped the actuators to verify that this is not the issue.
Checked blend door function.

On the tech 2 I can get the front hvac actuators to move in both directions, but the rear hvac actuators will not move all the way to cold or hot / floor or ceiling when I issue that command.

I’m leaning towards wiring or the hvac module.

Can anyone point me in the right direction. I can test the wiring for 12v and ground but don’t know how to test for the 5v signal. I have no ideas how to test the hvac module itself.

Thanks
David

Hi David, what is the part number of the actuator that you used?

 

[Doubeleive]

as james noted above, the correct part number has to be used, some will have the same amount of pins and fit perfect BUT are not the right actuators

 

[14Nali]

thanks everyone!
The actuator part number is 15-73644.

I have done some circuit testing.
When testing the low reference circuit I get a reading of 337 ohm. I think I now need to pull the hvac control module and test for continuity on this wire.

12 volt and 5 volt tested ok.


If the wire isn’t bad I believe this only leaves the hvac control module. Is
It common for these to go bad? Seems silly this would be bad on just the low reference circuit.

 

[Geotrash]

thanks everyone!
The actuator part number is 15-73644.

I have done some circuit testing.
When testing the low reference circuit I get a reading of 337 ohm. I think I now need to pull the hvac control module and test for continuity on this wire.

12 volt and 5 volt tested ok.


If the wire isn’t bad I believe this only leaves the hvac control module. Is
It common for these to go bad? Seems silly this would be bad on just the low reference circuit.

It’s not common, but it’s also not unheard of here. The electronics on these rigs are aging and we’ll start seeing more of these problems crop up as they go. My old ‘94 Acura started having multiple modules go bad in the last few years I owned it - usually the capacitors on the boards.

 

[14Nali]

Hi David, what is the part number of the actuator that you used?

View attachment 410785

This is helpful. Attaching some other documents I have been using.

 

[14Nali]

Had some time this morning. Pulled both actuators re clocked them to be centered. Reinstalled, cleared DTC with scan tool and disconnected battery this time around.

So far so good. No clue why discounting the battery is needed in addition to clearing the DTC, but that seems to have done the trick. I think having both new actuators installed on center probably helped.

 

[swathdiver]

I've never had a good relearn the manual way, always needed the Tech-2 for them to function correctly after replacement.

 

[14Nali]

Appreciate all the help. Hopefully the next person to have this issue can resolve it quickly. Those actuators aren’t easy to get to either!