Auto/AC default setting

I believe when the heat starts up it will slowly bring up the fan speed and keep it on your feet until it senses that there's enough heat to bring up the cabin temperature. I believe by design it will keep whatever air is coming out directed towards your feet so it's not blowing cold air at you. As the vehicle warms up, it starts gradually adding upper body.

Keep in mind this is how I remember it working. I'm in Phoenix so I don't use the heat much. It was 84 degrees today and even on the drive in to work I had all 4 windows down. I'm not what you call an expert in using the heat in any vehicle... but when I used it a couple of times last year that's how I remember it working.

 

You can change the direction of air flow on the MFD. However, when you make the change, it will no longer be in Auto AC. I don't know of any way to change the defaults of Auto AC. It will direct the air flow based on inside and outside temperatures and change the flow to upper, lower, or both vents as conditions warrant.

 

Also, the "upper body" part only uses the outer two vents in the dash, not the centre ones. They are for cooling.

I gave up trying to out think the system. It's programmed to do what it does and I don't think you can change it. I just got over it and now let it do its' thing. It works fine.

 

That is how mine worked this morning. I left for work real early and it was a bit cool. I turned on the Auto A/C and got heat on my feet. After a while, I started feeling it coming out of the upper vents.

 

You can change the defaults, but it has to be done at the dealership. Do a search for changing defaults and you should find the thread about this subject.

 

Go to this site for the information on changing the defaults

http://www.evnut.com/prius_mods.htm

 

Nothing there about the OP's question...

 

Sorry about that -- wrong site,. As I said before the last post, go to the search and look for Changing the defaults. I will also look and see if I can find it. As of now I have to go shopping with the wife......

 

The air from the side face vents during lower-demand heating conditions is to help keep the windows from fogging up. To conserve heat, the system uses recirculated air for the foot vents, but doing so alone would cause too much moisture buildup in the cabin, and thereby steamy windows. So they allow a separate flow of heated outdoor air through those side face vents to keep the air near the windows a little dryer.

If you don't believe me, feel the difference in temperature between the side face vents and the floor vents when it starts doing that, but before the cabin has really warmed up. The floor heat vents will be much warmer than the side face vents.

 

I am back from Thanksgiving trip...

I found the file that lists the Customized Body Electronics System. Do a search for " multi5.pdf ". This is a list of things that can be changed. But the dealer has to do them unless you have a tester.

Tom

 

Believe it or not, the need to direct hot air down to the feet as opposed to the upper vents, goes way back to the early days of the auto. Since warm air is less dense than cold air, it rises. Directing heated air to the feet will heat the car better as the warm air rises to fill the cabin.

The converse is true about cold air and is why the A/C directes air out the upper vents.

Sounds like Toyota took this to the next level when they direct recirc air at your feet and outside air on the windows. Cool.