'10 Limted; Auto Setting = little defrost

[Dag06XLT]

With it getting cold now, when I set the HVAC in 'Auto' mode, there is very little to no air coming from defrost windshield vents. When I manually select defrost/foot setting it blows fine so mechanically the upper vents are working. This Auto setting cause the defogging the windshield to take forever. My wife Acura always blows windshield and feet when it auto and enough to actually melt frost. This is first time with the Limited in the cold, had manual XLT before and always ran it in manual defrost/foot setting. I've done a search about blend doors issues, but everything works fine when pushing defrost/foot button. It seems the HVAC module isn't allowing it to push air onto the windshield. Is anyone else have this issue or is it normal? Thanks in advance!

 

[D Hook]

I always thought the Auto setting only controlled the temperature. I always select Defrost on the panel to direct air to the windshield. Have to check the owners manual.

 

[Dag06XLT]

Yep, first thing I did in case I misunderstood, but it confirmed how I thought it worked. Most Auto HVAC blows front vents and even recirc if needed to cool cabin quickly then blows windshield and floor when heating to keep windshield fog free and a more comfortable warming of feet and raising heat.

Owners Manual:

AUTO: Press to select the
desired temperature shown in the
display window. The system will
automatically determine the fan speed, the direction of the airflow,
outside or recirculated air to heat or cool the vehicle to the selected
temperature.

 

[tripplec]

It is normal. Read the manual if in doubt. The defrost button is there for a reason and also invokes the A/C to speed up the performance.

 

[D Hook]

Yep, first thing I did in case I misunderstood, but it confirmed how I thought it worked. Most Auto HVAC blows front vents and even recirc if needed to cool cabin quickly then blows windshield and floor when heating to keep windshield fog free and a more comfortable warming of feet and raising heat.

Owners Manual:

AUTO: Press to select the
desired temperature shown in the
display window. The system will
automatically determine the fan speed, the direction of the airflow,
outside or recirculated air to heat or cool the vehicle to the selected
temperature.

I think it's working as it was designed, just not such a great design. The air is directed to too many different locations, making them all sort of weak, too weak to do what you want. You can compensate by raising the desired temp which will increase the fan speed and blow more air to all the vents. Or you could just push the defrost/floor button and, like tripplec said, employ the A/C function to help clear the windows quicker. I don't have my manual handy....what does it say about using the buttons other than "Auto"? On mine, it maintains the temp I select, even if I use the other buttons. So it stays in Auto, just focuses the air in the direction I want.

 

[tripplec]

Sorry I believe you misunderstood. On any North American vehicle and most imports (I have Sante Fe, son has the Explorer). AC automatically is turned on when you press the Defrost button. You will hear it cycling as long as the Defrost mode is on. Some vehicles have two selections. Split Up & front or All to the Window, but either way the AC is run to dry the air for fast defrosting of the window.

 

[D Hook]

Went out and tried mine. Started from cold. Set to "Automatic" and after the car warmed, air was directed to floor only and temp was maintained at 80°. No air from front vents, no air from defrost; only floor.

Pushed "Defrost" and air was directed to windshield and "A/C" button lit up. Can shut off A/C by depressing button but will defrost better with it on.

I believe that's the way it's supposed to work.

 

[tripplec]

Yes, sounds right. You should be able to also have floor and vent in the auto mode though, not just the floor.

 

[D Hook]

Yes, sounds right. You should be able to also have floor and vent in the auto mode though, not just the floor.

Yes, if I hit the floor/vent button, it deploys air from those two.

 

[Dag06XLT]

Thanks for the replies. It sounds as if mine is working as designed although poorly designed. All my other cars/trucks w/auto HVAC had a steady light flow of air up to the windshield to keep it fog free during winter.