Automatic climate control heater not working properly?

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.

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.

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

Sorry to resurrect an old thread, but I've noticed some odd behavior. Sometimes, when I turn on the AC it won't blow out of the dash vents but I can feel it blowing on my feet. Eventually after about 2 mins, it will flip and start blowing out the dash vents. I suspect it might be humidity related and it's trying to defog the windshield due to humidity, but I'm not entirely sure. It's just frustrating when it's hot outside and the AC isn't blowing in your face at first lol

Hi:

The airflow direction is controlled by what is called a mode door actuator. On your vehicle (if it is the same as above) it is electric. When you change the flow direction, the actuator moves a door to direct the airflow requested.

Oftentimes, the actuator will start to fail and can delay. However, often the issue is identified by a clicking sound. By chance, do you hear anything like that?

Let me know.

Joe

I actually just replaced the blend door actuator on both driver and passenger sides, so I'm familiar with those. I don't hear any clicking on the mode door actuator like I did on the blend ones before they failed.

I wasn't sure if this was be design since I've noticed it only does it on very humid days...

I think it is working correctly. They only have a temperature sensor in the front HVAC this is why the rear HVAC will not work the same on Auto for the rear because it does not know the rear temp.

I definitely think it's humidity related. Today I got in the van and the temp difference made my glasses fog up. Turned on the AC and it goes to defrost for a few mins before flipping to dash vents. I guess it's trying to remove any potential fog from the windshield?

Yep, that makes sense. To confirm there is no clicking noise correct? It cold be the mode actuator is going bad.

Yes there is no clicking noise at all. And if I manually flip it to top vents it will change immediately, so it must just be something with the auto mode that does it that way.

Yep I agree, it sounds like the system is working normally.