I didn't notice this last winter....
With the engine at operating temp I do not get warm air from any setting or blend UNLESS the car is rolling.
RPM does not seem to affect it. Road speed - even 5 MPH - seems to be the only thing that allows me to get heated air to come from the vents.

I did some searches but could not find anything to shed light on this strange new symptom.
I have some time left on my warranty, but the dealer is 100+ miles away. Any advice?

 

Have you checked your coolant level? If it's low (even a little), it won't heat. Your symptoms are classic of low coolant.

 

Is your interior fan working?

 

Dang-
Added about 2 pints of fluid and now have heat. Thanks!
I guess RPM does indeed have an effect.

 

Keep an eye on it for a few days as the level will drop as bubbles are evacuated from the system, don't want the same problem a week from now.

 

That's what I figured. Common issue. Now.....where is the leak? In my case, it was the water pump. They are failure prone.

 

 

 

Topped it off with the fancy red stuff from the Toyota dealer every 6 months or so and all is well. Only took 1/2 cup or so.

 

 

 

I am so happy I saw this thread. I had the same problem and I added coolant and it resolved my problem as well.

 

Low coolant was definitely the issue. Also, don't forget to burp it as Toyotas are known to get air in their system. That'll significantly help as well

 

 

Yes, it will. Jacking it up helps get all the air bubbles out of the system, but you should get most of it out if you can’t