Have had the vehicle 3 months. VIN 24xxx. The windshield fogged up pretty bad driving home tonight. We turned on the defog setting and it do anything. It was so bad we had to drive with windshield wipers on at low setting even though it wasn’t raining. I’ve sent an email in to service to get it checked out. Any suggestions? Thanks in advance.
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Defog sucks
- Thread starter GoCanucksGo1
- Start date
Atari2600
Active Member
Defog is for inside Defrost is for outside. Since you mention wipers that sounds like the outside of the window. High outside humidity and cold cabin temp?
From the manual.
The windshield defroster distributes air flow to the windshield. Touch once to defog the windshield (the button turns blue). Touch a second time to defrost the windshield (the button turns red and the heating and fan operate at maximum levels). Touch a third time to turn off and restore the air distribution, heating, and fan to their previous settings.
From the manual.
The windshield defroster distributes air flow to the windshield. Touch once to defog the windshield (the button turns blue). Touch a second time to defrost the windshield (the button turns red and the heating and fan operate at maximum levels). Touch a third time to turn off and restore the air distribution, heating, and fan to their previous settings.
This, make sure you are clicking the front defrost button ‘twice’ so the icon turns red and you use heat to defrost.
Pressing it only once will give a blue icon and cold air (which sucks for fog or frost)
As an aside, you may have some sort of dirty film on the windshield and the "high humidity" occasional wipe can result in obvious (and super annoying) smearing which can greatly impede visibility. Regular glass cleaner won't typically touch it, but something with a little more bite does the trick (i.e. I just use Meguiars Cleaner wax to cut through it and then follow that with a regular glass cleaner like Invisible Glass or Sprayway to remove the leftover wax).
Manually make sure A/C is ON. The "defrost" setting does not seem to do that. Makes a big difference as the AC (even with heat) removes the humidity.
so much reading comprehension fails in this thread....
fog on glass can develop on the outside or the inside surface. OP reported fog building up on the outside. Turning on A/C inside isn't going to help; it actually makes it worse. In this case, you need to raise the temp of the glass so it is above the current dew point. When it's muggy outside, dew points are high, so it's easy for the A/C to drop the glass temperature below it to cause condensation on the outside surface (think cold can of soda on a hot day).
fog on glass can develop on the outside or the inside surface. OP reported fog building up on the outside. Turning on A/C inside isn't going to help; it actually makes it worse. In this case, you need to raise the temp of the glass so it is above the current dew point. When it's muggy outside, dew points are high, so it's easy for the A/C to drop the glass temperature below it to cause condensation on the outside surface (think cold can of soda on a hot day).
Atari2600
Active Member
Everyone should download the PDF manual from their online Tesla account and read through it. The one I downloaded from Tesla was dated August 1st, 2018. The whole thing is 167 pages.
How will wipers help with defog???
To wipe off the condensation on the cold (below the dew point) windshield.
All I can say is: don't knock it till you try it. Works well for me with external condensation. Putting defrost on HI (tap twice so it turns red) works much better if AC is ALSO turned on.
Atari2600
Active Member
The solution you suggest will take care of both inside and outside situations. The downside is it uses maximum power.
Condensation on the outside of the windshield when using A/C is nothing unique to Model 3 or to Tesla. It happens on other cars as well, maybe all cars. I certainly have had it on my past Mercedes. It's just physics. It can happen on the inside as well, if the air is especially humid, and especially if recirc is turned on.
Thx everyone for the feedback.
Above is a very good point.
I found this explanation and advice to be helpful too (and, no, I don’t work for Allstate).
Tips for Clearing Up Foggy Windows | The Allstate Blog
I thought that it blows.
Every time I pass this thread I think, 'it is suppose to "suck" ...... or a better word would be to reduce the condensation out of the interior environment.'
So, maybe what was meant ..... that it doesn't "blow" conditioned, dry air as Rich966 suggest."
So many writers on this and other threads (and forums) use the word "suck."
It's used in such a variety of ways, it cannot imply "exhale or inhale." I'm not sure what the expression means ....
I suppose it means that .... whatever .... does not perform up to expectation?
Or, perhaps it is simply an inability to verbalize what the real issue is?
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