Front Defogger Switch Question

[timzter]

OK, to me the operation of the rear defogger switch on the 2010 ES350 makes sense. It starts off with NO defoggers turned on. I tap the rear defogger switch once. Its LED light comes on and the rear window gradually defogs from the heat of the heating element in the glass. I then tap the same rear defogger switch a second time and its LED goes OFF and the heating element stops producing heat. Makes sense.

But the front defogger switch is confusing! OK, so it starts off with NO defoggers turned on and the A/C fan is also NOT turned on. I tap the front defogger switch once. Its LED light comes on and the blast of air over the windshield gradually clears the fog away. I then tap the same front defogger switch a second time. Its LED light turns OFF and the blast of air stops blowing across the windshield, but now the AC's "Auto" light turns on automatically, and a full blast of air now comes out from the OTHER AC vents. (WHY???? I did NOT request for the AC to come on!!!) I must tap the AC "Off" button to turn the AC off.

If after the front defogger LED comes on and the blast of air blows across the windshield and I tap the AC OFF button instead, the blast of air across the windshield DOES stop, but the front defogger LED remains LIT. So now if I want to REALLY turn OFF the front defogger LED light, I must tap it yet again, but, of course, this causes the AC's "Auto" to be engaged and the full blast of air comes through the other vents like I described above.

Why is the behavior of the front defogger switch so damn confusing? What am I missing here? Why did they not make it behave exactly like the rear defogger switch??? Keep it simple!

(Yet another thing I don't like about the Lexus ES350. Perhaps it behaves the same way in the higher models!)

[pj8708]

I don't care for the air blowing on me either. But, here is how it works. (This info. can be found on pages 205-207 in the owners manual.)

The front window defogger will always operate in the outside air mode. So if your system is using the recirculating mode while your driving, or is set in that mode when you start up in the morning, it will always automatically switch to the outside air setting. This also puts the system in the AUTO mode so that the system can control the temperature as you have set it. Additionally, the A/C comes on at this point to reduce the amount of moisture/humidity in the cabin air. When the window and cabin air has been defogged, the fan slows and the air is partially directed through the dash vents. The system stays in AUTO and the A/C stays on. If you don't want this, you have to change both settings. Just the way Lexus does it.

From your description it sounds like your ES does not have nav. If it does have nav., it still operates the same way.

[timzter]

I don't care for the air blowing on me either. But, here is how it works. (This info. can be found on pages 205-207 in the owners manual.)

The front window defogger will always operate in the outside air mode. So if your system is using the recirculating mode while your driving, or is set in that mode when you start up in the morning, it will always automatically switch to the outside air setting. This also puts the system in the AUTO mode so that the system can control the temperature as you have set it. Additionally, the A/C comes on at this point to reduce the amount of moisture/humidity in the cabin air. When the window and cabin air has been defogged, the fan slows and the air is partially directed through the dash vents. The system stays in AUTO and the A/C stays on. If you don't want this, you have to change both settings. Just the way Lexus does it.

From your description it sounds like your ES does not have nav. If it does have nav., it still operates the same way.

My ES *does* have Nav. Anyway, I don't like the way this front defogger switch behaves. Seems like every time I use it, I have to tapdance around it and the AC OFF switch with my fingers to turn the front defogger LED off. Totally not intuitive.

[SW03ES]

Have you ever owned a car with automatic climate control before? I've owned several different cars with automatic climate control before, and all of them operate the same way. If you just leave the thing in "AUTO" all you need to do is set the temp. If you need the defroster, hit the defroster button. When you no longer want the defroster, hit "AUTO" again, and all goes back to normal. Its not like the rear switch because the rear defogger doesn't interact with the rest of the climate system. To use the defroster in the front you have to route air away from the vents and underdash ducts. Its the same way on every other car as well, as long as they don't have a heated windshield.