HVAC Air Flow Issue

[dkreller]

So I have a 2009 Tahoe LTZ. I’ve been trying to diagnose my ac issue with no luck. I have dual climate control in front. The driver side is functioning just fine; however, there doesn’t seem to be any temp control on the passenger side. Ok I’m thinking blend door actuator, right? Well the air flow on the passenger side is almost nonexistent. I can’t feel any air coming out of the defrost or at the feet either. Does the blend door have any affect on air flow speed as well? I mean I have the ac on high and there’s barely anything coming out of the passenger side.

One other thing is I’ve noticed recently is my ac kicks on and off every 20 seconds or so when the vehicle is sitting idle. Any thoughts on that?

 

[Doubeleive]

So I have a 2009 Tahoe LTZ. I’ve been trying to diagnose my ac issue with no luck. I have dual climate control in front. The driver side is functioning just fine; however, there doesn’t seem to be any temp control on the passenger side. Ok I’m thinking blend door actuator, right? Well the air flow on the passenger side is almost nonexistent. I can’t feel any air coming out of the defrost or at the feet either. Does the blend door have any affect on air flow speed as well? I mean I have the ac on high and there’s barely anything coming out of the passenger side.

One other thing is I’ve noticed recently is my ac kicks on and off every 20 seconds or so when the vehicle is sitting idle. Any thoughts on that?

are the passenger side vents open? the only thing the passenger side blend door does is regulate hot or cold air, you can look inside the vents with a flashlight and roll the control up&down to verify.
ac kicking on/off could maybe be low r12 that might take a gauge to check pressures and stuff I am no expert but that would be my first guess.

 

[dkreller]

are the passenger side vents open? the only thing the passenger side blend door does is regulate hot or cold air, you can look inside the vents with a flashlight and roll the control up&down to verify.
ac kicking on/off could maybe be low r12 that might take a gauge to check pressures and stuff I am no expert but that would be my first guess.

Yes the vents are open. I even removed the outer trim cover to verify everything was lined up properly and still hardly any air flow.

 

[Doubeleive]

Yes the vents are open. I even removed the outer trim cover to verify everything was lined up properly and still hardly any air flow.

that's odd, well if you want to dig further in I have a video of how to remove the passenger side blend actuator, maybe pull that out and see if the door moves by hand or if it broke or something and is blocking the vent, there shouldn't be any other reason for the left & right side to have different air flow unless something is blocking the vent

 

[89Suburban]

Try a hard reset. Mine acted up a year ago and that worked for me.

 

[Doubeleive]

Try a hard reset. Mine acted up a year ago and that worked for me.

Depending on how much less airflow there is from side to side it might be normal with more to the driver, checked mine which should be working normally
Drivers side

Passenger side

 

[dkreller]

So after dash removal, I’ve got a broken blend door on the passenger side. Any ideas on how to access this bastard?

 

[Doubeleive]

So after dash removal, I’ve got a broken blend door on the passenger side. Any ideas on how to access this bastard?

nope, dorman makes "some" blend door repair kits not sure if they make any for these vehicles or not, you might end up having to cut it out and replace with another good used section and use hvac tape to put it back together, I have seen that done on some Silverado's on youtube before

 

[dkreller]

nope, dorman makes "some" blend door repair kits not sure if they make any for these vehicles or not, you might end up having to cut it out and replace with another good used section and use hvac tape to put it back together, I have seen that done on some Silverado's on youtube before

Well I repaired my blend door and put it all back together and there is no improvement with the temperature on the passenger side. I guess I will try a hard reset tonight and see if that helps.

On a positive note, my radiator fans and ac compressor on/off issue is now resolved after topping of the engine with motor oil. It took 4 quarts. I'm not surprised as I am due for an oil change. I think I will start getting my oil changed every 5K miles now.

It's crazy how many sensors are tied together and even crazier how a check engine light doesn't even come on in some instances.

 

[Doubeleive]

Well I repaired my blend door and put it all back together and there is no improvement with the temperature on the passenger side. I guess I will try a hard reset tonight and see if that helps.

On a positive note, my radiator fans and ac compressor on/off issue is now resolved after topping of the engine with motor oil. It took 4 quarts. I'm not surprised as I am due for an oil change. I think I will start getting my oil changed every 5K miles now.

It's crazy how many sensors are tied together and even crazier how a check engine light doesn't even come on in some instances.

4QTS? should have been a check oil message on when it is 2qts low
as for the hvac if there is air flow but the temperature is not changing then you may need to replace the actuator I showed in my video, if the recalibration does not work, you can watch it visually with the dash trim off, just use a flashlight and watch the notches on the metal gear sticking up, set all the way to cold it should move all the way one direction and stay there, same for hot it should move all the way the opposite direction and stay there, medium temp setting will make it pretty much stay in the middle.

 

[dkreller]

I replaced the actuator when I repaired the blend door.

 

[PPV12HOE]

Your issue is air flow related and not temp related...? The blend door regulates temperature where as the mode doors regulate where the air comes out i.e. floor, dash, or defrost... have you checked air flow from any of the other vents... you could have a non functioning mode door or actuator... with dual climate control there are two actuators and two doors for everything one for each side... unfortunately repairing a lot of these includes dash removal and heater box removal for the doors... not a lot of fun...

 

[dkreller]

Your issue is air flow related and not temp related...? The blend door regulates temperature where as the mode doors regulate where the air comes out i.e. floor, dash, or defrost... have you checked air flow from any of the other vents... you could have a non functioning mode door or actuator... with dual climate control there are two actuators and two doors for everything one for each side... unfortunately repairing a lot of these includes dash removal and heater box removal for the doors... not a lot of fun...

I figured it out. My repair job on the blend door apparently didn’t hold up. I’m waiting for a new one to come in so I can redo everything.

Yay!!

 

[dkreller]

I figured it out. My repair job on the blend door apparently didn’t hold up. I’m waiting for a new one to come in so I can redo everything.

Yay!!

Ok here we are after another dash removal. I installed the new blend door and changed out the actuator. Now my thermostat is reversed on the passenger side. Hot = cold and cold = hot.

I’m at a loss on this one. Tried resetting the system a few times and no luck.