On a 2001 Honda Civic. Having the temp dial to HOT. When I turn the air flow dial from FRONT to Defrost (windshield), it turns on the A/C button and the A/C motor kicks in also. It just started doing this. So now I can't defrost my windshield. Air flow does come out the windshield. No check engine light. Please help.

1 Answer 1


This is normal behavior. The A/C system is turned on to dehumidify the air, which causes the windshield to defog. Without it, your breath would freeze on the inside of the windshield and cause further issues.


  • Please note Bob Cross' comments below.

  • I found instructions on the Honda Tech Forum which is supposed to give you full manual control over this, but warn you I do not suggest you do this, nor do I know if it actually works. Please perform at your own risk:

DIY: Turn Off Automatic A/C Turn-On What you will need: Two Fingers

Time Needed: 10 seconds.

Annoyed with how you can't turn off the A/C when you turn to defog? Here's the override (realize that A/C expediates the defog process).

  1. Turn Car Off
  2. Turn Temperature Knob To Full Blue (All the way to the left - Counter-Clock Wise)
  3. Turn Vent Knob To Off (All the way to the left - Counter-Clock Wise)
  4. Hold Down Air Recirculation Button As Well As A/C Button
  5. Keep Both Buttons Depressed and Start Car
  6. Keep Both Buttons Depressed for 7 Seconds

You will now have control of your A/C regardless of what setting you are in, to revert back, simply repeat the procedue.

  • 6
    Might want to add points like: 1. some cars do not defrost well when set on recirc (like mine) and 2. it'll make nice hot air once the car heats up. Just because it says "A/C" doesn't necessarily mean that it's making the car colder.
    – Bob Cross
    Commented Jan 30, 2014 at 17:25
  • @BobCross ... You are quite right ... most vehicles which do this do not even allow you to put it on recirculate when on defrost. Commented Jan 30, 2014 at 17:52
  • 1
    Well, mine does. I slide a lever from left to right and a little flap goes clunk. Recirc!
    – Bob Cross
    Commented Jan 31, 2014 at 2:51
  • @BobCross ... Then I suggest your vehicle is not "most vehicles" ;-) Commented Jan 31, 2014 at 11:39
  • does this work for Toyota as well? ToyotaJoe
    – user6236
    Commented Jun 13, 2014 at 19:04

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