Automatic climate control heater not working properly

2011 HONDA ODYSSEY
201,079 MILES • 3.5L • V6 • 2WD • AUTOMATIC
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ETERNALARIANNE
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I recently got this van a few months ago and have a question about the automatic climate control. For reference, I keep it set on 67F all the time with the front and back set to sync.

It seems to function as expected when using A/C - it will ramp up the fan and cool the van down, blowing out all vents. Normally it keeps it on outside air intake, but if it's really hot outside, it will switch to inside air circulate to cool down quicker.

My question is about the heater. It seems to only blow out the front floor vents at a low fan speed. I can take it off automatic and tell it to blow out the dash vents and it will start coming out the back vents as well, but it never blows out the back vents if it's on automatic. It also never switches to inside circulate, no matter how cold it is outside. Is this normal operation for the heater on automatic?
Nov 28, 2021 at 5:57 AM
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JACOBANDNICKOLAS
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Hi,

It sounds like it is working properly. The only question I have is if you turn the heat to max, do you get any heat from the rear?

As far as the recirculation in heat mode, that is because it creates moisture/condensation on the windshield if fresh air doesn't enter the vehicle.

Now, if you take a look at pic 1 below, it gives a better description of how the system works. It sounds like you have the tri-zone climate control. The description in pic 1 explains how the system determines when and where to send the airflow and temperature. Things are simply getting more and more complex. LOL

The last pic simply is a visual of the system. It indicates AC, but it functions the same with heat.

I hope this helps. Let me know if you have other questions.

Take care,

Joe

See pics below.
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Nov 28, 2021 at 8:12 PM
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ETERNALARIANNE
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Yes, if I put it on max fan and set it to blow out the dash vents, it will start coming out the rear. If I leave it on floor, it never comes out the rear. I guess I never noticed a problem on A/C since A/C always comes out the dash vents, not the floor.

Why would auto heat only blow on the lowest fan setting though? I think maybe I've heard it ramp up a tiny bit a few times, but it never gets full blast like the A/C does on auto.
Nov 29, 2021 at 3:58 AM
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JACOBANDNICKOLAS
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Hi,

Interestingly, fan speed is determined by what the system sees is needed. Like you, I've had others question the same things. In automatic, the module controls everything.

I hope this helps. Please feel free to let me know if you have other questions.

Take care,

Joe
Nov 29, 2021 at 4:47 PM