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.


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 Jan 30 '14 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. – Pᴀᴜʟsᴛᴇʀ2 Jan 30 '14 at 17:52
  • 1
    Well, mine does. I slide a lever from left to right and a little flap goes clunk. Recirc! – Bob Cross Jan 31 '14 at 2:51
  • @BobCross ... Then I suggest your vehicle is not "most vehicles" ;-) – Pᴀᴜʟsᴛᴇʀ2 Jan 31 '14 at 11:39
  • does this work for Toyota as well? ToyotaJoe – user6236 Jun 13 '14 at 19:04

protected by Pᴀᴜʟsᴛᴇʀ2 Dec 8 '18 at 17:10

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