[sg11]

So I was driving down the road the other morning and it was humid out and my front windows started to fog up so I did what Ive usually done with other cars when this happens which is to turn on defrost and that usually clears up the windows but that didnt work. I actually had to turn on the ac then they started to clear. Is this normal?

 

[bananaboat]

Yes, the majority of vehicles kick on the compressor when you set the control on defrost. A few including the Mazda 2 require you to press the AC button. I have an old Miata that works the same way.

On a side note, I had a Datsun back in the 70's that worked the same way but it had a nice feature. The AC had a prestart setting. This would remove the heat from the AC vents without blowing any air. After a few seconds, just turn on the AC and it would blow cold air without the nasty heat at 100+ degrees.

 

[2oom-2oom]

Don't forget to set the air intake slider to Outside air, too. The A/C system doesn't just cool the air, it removes water vapor, too. This makes it ideal for defogging, and it works even if the Temperature Control is set for heat.