Rear Heat Problem

[brodg]

with the actuator off can you move the door by hand?

 

[brodg]

also if it sets a code it will default the actuator and not move until the code is cleared try disconnecting the battery for 5 minutes.

 

[stephendudra]

more information

Sooooo I seen two messages and thought that I would answer then.

Yes, with the actuator off, the door can be moved manually.

I never got any codes for anything. But! When I installed my new PCM programmed by Justin with blackbeard, I had the negative side of the battery off for well over 30 minutes. So I know that it isnt a code.

I put 2 new actuators on it and STILL it would not move the door from hot to cold.

Isn't there a 3rd electrical actuator for the rear ac somewhere under the dash?

 

[JChampion]

I have a 2000 Chevy Tahoe and have heat problems for a year now. Sent it to the dealer with no front heat & back heater working great.
Ends up I needed a new front heater core because it clogged up after 90K miles. Turns out 8 months later I lose the heat up front again. Now the Tahoe has a coolant filter mounted to clean out deposits. Everything works great for 3 months... now I have no heat coming from the back. Just cool air like I use to have up front. I'm figuring the back core clogged up. This thing has been a nightmare. I flushed the back core and got a lot of deposits out of it but still no heat. It might be too far gone.

 

[stephendudra]

Wow that does sound like a nightmare!

My issue certainly isnt that problem. There is a door that opens and closes for lack of a better explanation. There is an actuator that opens and closes this door. I have replaced this actuator and it still does not work. You can actually watch the actuator (if working) open and close this door. This is my problem, the door is not opening and closing.

I hope this helps!

 

[treee]

rear heat control problem

Hi i am having the very same problem with my escalade,
with mine the actuator that changes the temp was not moving but the one that directs the air high or low does. They both have the same # so i switched them nothing so i switched them back now the one that worked it dead also. I have checked all the same things you have. Doors are free will not work from the front or back. I did a wiggle test nothing no codes. I pulled one apart put power to the motor it's fine not sure about the circuit board. nothing visual looks fried.
Time for a repair manual

 

[martin]

Hello, just had this problem if you just want to have rear heat for winter this is what i did. take off the rear actuator, unplug then where the dial moves the vent door, it's black and hard to see. Move this knob counter clockwise and you will hear it open, this is where you will get heat. Then move bad actuator knob to aline with vent door and reinstall. You will have heat for winter, hope this helps.

 

[KevinHancock]

Hope this helps!

Hey guys I was looking through the web trying to figure out why my wifes rear heat was not working on my wifes 2006 Tahoe and came across this forum. I also found this service bulletin that may be of use to some of you. I also replaced the blend door actuator because is seemed to be "frozen" on the a/c side. Now it is stuck on the heat side and when I turn the ignition on it seems to "search" for position as this bulletin describes. I haven't replaced the auxiliary hvac control module as the bulletin calls for yet but expect that is what I will have to do. I am almost afraid to call GM and ask what one will cost. Anyhow here it is, good luck with your problems.

http://www.justanswer.com/uploads/Bluegorilla/2009-02-19_151400_2003-2006_taoe_rear_heat.pdf

 

[KevinHancock]

I just called our local Chevy dealership here in NC and they told me the part was 149.33 +tax. I looked on their parts website and bought the module, shipped to my house for 88.57. Hope it works.

 

[martin]

wow sorry, you could have bought it for 50.00 @ carquest

 

[PJS3]

wow sorry, you could have bought it for 50.00 @ carquest

And of course, I call carquest and they don't have the part there... sigh...

 

[borumca]

Try this first!

Hello guys! firs of all, I don't know much about cars.
As many here I had the same problem, was getting intermittent heat in front and No rear heat on my 2005 Tahoe. Looking for the fix, I came across this forum. To fallow the recommendations from here and other forums to fix the problem, I made a list of steps to fallow based from what I have read. got my tools, the list and WAS ready to start taking stuff apart. :superhack:

1) My battery was replaced some time ago and some one suggested to disconnect the battery and touch the two cables together for 30 seconds, this will completely discharge and reset all the modules in the vehicle . connect battery back and see if the problem was fix.
If not fix step two
2) take off the rear panel and buy and replace the temperature door actuator and see if is fix.
If not fix step three
3)buy and replace the mode actuator
If not fixed, step three
4) buy and replaced the auxiliary hvac control module and see if is fix.
If is not fix, step four
5)check for bad heater hose valve buy, replace and see if is fix.
If not fix. step six
6) sit down and CRY!!!

But BEFORE I did all that knowing that the heat comes from the water heated by the engine, I decided to check the engine coolant level and what do you know, it was LOW IN COOLANT so I top it up and Viola! it fixed the problem, heating inside the car works great!!!!

I'm sure this will not apply for everyone here but may help some one as lucky as me that the problem is just low in coolant!
:happy160:

 

[Solo132]

Hey I have a 03 Tahoe Lt front vent heater works good back blows cold air I set the back controls to hot and the front controls for the back to hot still nothing still blows cold any tip