I have a 04 Limited without the Nav system and it does the same thing.

 

i think thats a atomatic default from the factory. My 2002 highlander ltd does it too even without the navi, it annoying in the winter time. i just dont us the climate control in the winter time.

 

I've also got a 2004 Highlander with the nav system. I don't have that problem. I can leave the climate controls on automatic, and unless I touch the A/C button on the screen, it stays off. I'd complain to the dealer. What you describe is unacceptable.

 

It's likely the A/C indicator is on, but the compressor on most cars will not run automatically below 25 or 35 degrees. Above that, it runs to control moisture fogging when Auto is selected.

 

I have the same issue in my car, but it seems as though it says "air conditioner," but it is really throwing out heat at the climate temp you set manually - 74 degrees, etc...
I have found that it simply uses the words air conditioner for everything, even if it is the heat.

 

I have the same issue in my car, but it seems as though it says "air conditioner," but it is really throwing out heat at the climate temp you set manually - 74 degrees, etc...
I have found that it simply uses the words air conditioner for everything, even if it is the heat.

I don't pay any attention to the fact that it says "air conditioner". It's the fact that the light over the air conditioner button stays on and it runs the compressor.

It will even run this in cold weather because in order to defrost the windshield, etc., you want the compressor on.

 

My 2005 Sequoia and my 2003 Highlander both do the same thing when AUTO is pushed it is annoying to push the A/C button to turn it off everytime. I would leave it on but knowing the A/C compresser is on just bothers me because you loose a little Horsepower and GAS. In the winter I just hit the AUTO button then turn off the A/C and if you turn your truck off like this you won't have to do it again it remember's the last setting. (work's well with Auto Start) John

 

All modern automotive HVAC systems use the same duct work for the heater and A/C. When you use the automatic climate control, the A/C compressor comes on to remove any moisture in the air and then it passes over the heater coils where the air is heated to the temperature you have dialed in. The dry air is blown into the interior where the moisture is absorbed and that air is either recycled or dumped outside. It is not very efficient to run the compressor in the winter, but the windows do not fog up as much when it is running.