Hi All,
2009 LR3 blowing warm air on passenger side face vents when AC is on. Driver side AC is fine blowing cold. Rear AC is fine. Checked all fuses, they are fine.
Blower is also working fine. Blower control module is hot to the touch and looks fine.
I've read many threads pointing to blend motor door that could be stuck on the right passenger side which runs separate from the left driver side. The only door i can see in action is above the blower when i removed the air cabin filter where i can see the door opening and closing when AC is turning on/off. My understanding is that to reach the blend motors, i have to remove the center console (radio, navigation, etc).
Any ideas where the problem could be before taking things a part?
I have IID control code reader but no faults with HVAC
Thank you in advance for the help

 

Today i removed center console, radio, navigation, all the panels to reach the 5 denso motors that control the HVAC. I was able to reach 3 so far and they seem to work fine.
AC is blowing cold on left side but normal air on right. When i move the arms manually to close the doors on the HVAC that are connected to the motors, I can get hot air on both sides.
Would this be a problem with heater Core? if so why one side is cold and other is warm.
I am trying to understand the 5 motors that control the HVAC. Are 3 of them has the same function while the other 2 has a different function?
anything i do the temperature stays warm or right front side.
Any help will be appreciated.

 

The heater core is single flow design, meaning its one core. Not split like on my BMW which thus has three coolant lines (too hot, one return). And from what I can tell, there is no heater valve to control flow, so the core is always flowing hot. Typically when an LR# core goes bad, you get the opposite issue - cold on one side, driver side. This is from scaling deposits and crap that builds up and settles on that side/corner.

You can do a self-test of the HVAC.

The motor and flap operation can be checked using the on-board distribution motor self-test function.
The self-test can be initiated by pressing and holding the ECON and RECIRC buttons while turning the ignition switch to the ON position.
The control module will then compare the current motor position with the values stored in the module and will indicate an error by flashing the ECON LED (light emitting diode).
If there are no errors, the LED will go out and the system will function normally.
To confirm that there are no errors, turn the ignition switch to the OFF position, then back to the ON position.
Observe the operation of the programmed defrost LED.
If there are errors present, the programmed defrost LED will flash and the system will attempt to calibrate itself.

 

Also you can bypass the heater core if you don't need it, just loop it back on itself and seal off the core.

EDIT: on note on above as a person had a problem getting the procedure to work:

I did eventually get the procedure to work. I got an error flash once, then the system seemed to reset. I appear to have a happily working HVAC now.

 

Thanks Dakota Traveler.
The self teuton the HVAC shows no errors. My diagnostic tool (IID GAP) also shows no errors.
I checked the refrigerant
60 with car running,AC off
20 with AC running
Is this normal or low?
I will try to add refrigerant and report back before i further troubleshoot.
I live in Dubai. I don't need the heat at all. I like your idea of bypassing the heater core, but have no clue how to do it.
I noticed that the two aluminum pipes that are coming into the heater core are very hot. Isn't one supposed to be cold.
I have a rear AC blower with 2 hot and 2 cold pipes which i think is independent form the front, correct me if i am wrong.

Can heater core be cleaned? just wondering

Thanks

 

Front heater core has an inlet pipe an outlet pipe. They both should be hot when the engine is running. The coolant simply passes through the core. There is a diagram available showing the air flow through the Hvac system and how the various doors direct or deflect the airflow. It is here on the forum. Not sure of the date or post but you can find it. I have a blend door issue on the lower driver’s side that I can’t resolve. Gap tool shows a fault and the Servo motor is out of sync but I cannot get it to work. For me it is no heat on the driver’s side. Ac is fine. Good luck lots of info here on the forum. Phil

http://www.disco3.co.uk/gallery/albu..._Operation.pdf

 

See the attached link.

http://www.disco3.co.uk/gallery/albu..._Operation.pdf

 

Do not add refrigerant unless you need it, you can damage a system by overfilling. And it does not sound like cooling is the issue. It has to be an HVAC control issues. If tests come back fine, its something physically broke most likely.

You can clean a heater core, but it has nothing to do with your issue.

I am not sure which engine you have, but take a look at this. With most of the engines this should be accurate enough. If you want, clamp off the supply hose (pink) to the core. I think this supplies both front and rear heaters. You can damage the hose by clamping too hard, so be careful. But if you clamp it off, it will stop or greatly reduce the coolant flow. Then you can get an idea of how things work. Instead of looping back the core, you could also cut the supply hose and insert a valve that you can open/close. So in the future you can properly purge coolant when changing.

 

Thanks Ljdiscovery...

You can swap left and right servo motors to check if it is working. It is tricky to put them back in place but i managed with mine.
It is puzzling to me that when i have AC on, cold air only comes out from driver side and warm air from passenger side. If low in refrigerant, wouldn't both be same temp?
Or one door is stuck somewhere?
When i turn the ***** to heat, it gets very hot...so i am assuming that the doors are fine...

 

Because you are not low on refrigerant. Or at least not low enough that its not working. You need to solve your heat issue before deciding you have an cooling issue. They are two very separate systems only separated but eh flap doors in the HVAC.