Hello, I am having an issue with my rear heat on my 2005 Tahoe 5.3 LS. I have the issue of "unable to control rear HVAC temp". The mode setting for air circulation works fine. The speed adjustment for the blower works fine. The warm to cool adjusment wont change at all. Currently the system is stuck in the cold position. I hooked into my friends system (he has an actual system hat can diagnose and reflash my truck) And it provided the bulliten to repair DTC B0434. The worksheet advised to replace the temp control module and I did. We had checked the temp door itself and it moves just fine...the actuator is getting power and I even went as far as to by a new ACDelco Actuator and tried a install and reflash with no luck. Everything has power as it should and volts seem to be ok. We can actually make the actuator work with his system and reset the paramiters for travel but as soon as the system resets.... the code B0434 comes back and the warm and cold function wont respond. This has been tricky for me to say the least..I am bald and have no hair to pull out..I dont want to resort to head bashing on my wall...Any help would be great. Thanks a bunch!
2005 Tahoe Ls 5.3 Rear air issue.
- Thread starter sutphen1
- Start date
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With the code your getting I cant offer my normal round of advice concerning loss of heat to the system (if you've had a coolant change/flush would need to purge the system of air, which will bring back the heat) but its not looking like the case.
With the code your getting I cant offer my normal round of advice concerning loss of heat to the system (if you've had a coolant change/flush would need to purge the system of air, which will bring back the heat) but its not looking like the case.
kses123
kses123
I had mine stuck on cold over the summer. I had to replace the actuator as well as the little computer that controls the actuator. They came out with an updated part to fix the problem that causes these actuators to die.
Yep thats what we did too. I actually replaced both the Temp module and the actuator. The actuator wont even search after the code comes back from the reset. When the system is under the control of the diagnostic system it works in full. The rear air control center up front is my only other wonder if maybe the warm to cold control is not working out of that whole cluster. The controls work for fan speed from up front and the vent control works too...just no response from the temp control. The rear control for the middle seats wont change the temp either but will control fan speed and vent position. This really has me stumped...First time my "Hoe" isnt reponding to fixes!!! I will ask about an update or search about that. My Tab is up already for parts just dont want to over buy for maybe a ground issue?? Thanks for getting back.
---------- Post added at 03:58 PM ---------- Previous post was at 03:48 PM ----------
Thanks...nope no work of that sort recently. This happened rather on its own and very out of the blue. The system worked then it didnt. I live near Cleveland and it is now getting cold so the blend of warmer air was used recently and this is when we found out...All summer the air was cold and would work at all fan settings and vent postitions from both the front control unit and the control unit available from the rear seats. All of that is working the only issue is the actuator wont move the temp blend door at all...and the door will move by hand and hot and cold air will mix by the manual method but when any of the controls are use to send a signal for the acuator to move and create a blend then no luck...there sits the actuator still as could be...but all works when we capture the system settings via the diagnostic system my friend has. The actuator travel settings are all good and it isnt like the range is off. a soon as we reset the code the system reacts by sending the actuator all the way to full cold and then the vehicle control for the warm and cold blend dont work. I di install a new air temp module and acdelco actuator just to eliminate both rapir suggestions for the code provided from the system. Still no luck.
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yea I am tracking the actuator issue as well, was just hoping something easier was at hand. I am actually experiencing the same issues so I have been doing a lot of searching to try and get my rear heat back up.
Going to pull mine tonight and see if it maybe got stuck, figured I'd start with the cheapest option and work my way back. Do you think disconnecting the battery for a few could help reset things? When you say the diagnostic tool works but it wont run regularly on its own nor will it KEEP the settings, Im inclined to try pulling the power source to the vehicle in hopes of a reset of things. Just another thought, I know it seems you're running out of options so trying to put them all on the table!
Going to pull mine tonight and see if it maybe got stuck, figured I'd start with the cheapest option and work my way back. Do you think disconnecting the battery for a few could help reset things? When you say the diagnostic tool works but it wont run regularly on its own nor will it KEEP the settings, Im inclined to try pulling the power source to the vehicle in hopes of a reset of things. Just another thought, I know it seems you're running out of options so trying to put them all on the table!
kses123
kses123
Do you think the hvac controls on the roof in the console could be bad? That is the only other component of the system I believe.
That is comming up as the last thing I can think of. May pull that part and test the output. May be no good but why does my rear control for the rear seat not work then?? Both ways one could control the temp blend dont work for the rear blend....that what made me think that it wasent just the overhead control but something else along the way. Thanks man!!
---------- Post added at 04:22 PM ---------- Previous post was at 04:19 PM ----------
I'm going to try this after supper...I may disconnect the fuse for the rear hvac system...and the battery...re connect the battery and run truck...then shut down and disconnect battery again...replace fuse and then hook back up the battery and start again...this may make the system re learn the control again..or not...Thanks again!!!
kses123
kses123
The rear hvac is controlled two different ways. On the back of the console, it is control via a Class 2 data line. From the overhead console, it sends different voltages to tell it what to do. Did you replace the module in the back with part # 15832319? I think that is the updated module. What happens if you swap the actuators around? Like moving the temp actuator to the mode door. Does anything happen differently? Perhaps the new module you got was bad...it could happen.
---------- Post added at 04:26 PM ---------- Previous post was at 04:24 PM ----------
If you try this, make sure to follow the proper procedures for re-learning the hvac up front! Sometimes when people change batteries, the HVAC up front gets confused and that is when the actuators start to go bad. Stuck on hot or cold, etc. It's quite annoying!
---------- Post added at 04:26 PM ---------- Previous post was at 04:24 PM ----------
If you try this, make sure to follow the proper procedures for re-learning the hvac up front! Sometimes when people change batteries, the HVAC up front gets confused and that is when the actuators start to go bad. Stuck on hot or cold, etc. It's quite annoying!
Hey thanks man....I didnt even think about that...My luck i will be stuck in full cold all the way around and puting a new meaning the color Summit White!!! And yes that is the part number I had sent. So maybe it's the update I need to do? I have not swappwed actuators but volt checked the harness and it was in the right voltage levels so i know for sure the wiring at the actuator is sending the correct power...will work more in a bit and will stay away from that system battery reset until i look into the front reset process..Thanks guys...
I am having the same problem my rear is blowing cold air and does not blow out hot air as well. I guess I have to change out part 15832319 does anyone know the proper procedure to relearn the front? If you can e mail me I would appreciate it ..
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