# A/C of the car (CIVIC 2002, LX) is always on **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** airconditioning\ **Created:** [October 11, 2007, 3:20pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813 "2007-10-11T15:20:36Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![asheoran](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@asheoran](https://community.cartalk.com/u/asheoran)\ **Post date:** [October 11, 2007, 3:20pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/1 "2007-10-11T15:20:36Z")
I bought a Honda Civic 2002 4-5 weeks back. Its A/C is always on. When I push on the A/C knob it does not turn off, and the light in the knob is always on, and of course A/C is on as well. I can turn it off after trying several times for few days. However, if I turn the fan on or press another knob, the A/C automatically comes back on again (the A/C knob has its light on) even though the A/C knob has not been touched. Can you suggest where the problem could be and how it can be resolved. Thank you for help. ---
**Author:** ![Beadsandbeads](https://avatars.discourse-cdn.com/v4/letter/b/c57346/32.png) [@Beadsandbeads](https://community.cartalk.com/u/Beadsandbeads)\ **Post date:** [October 11, 2007, 11:42pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/2 "2007-10-11T23:42:47Z")
Check the switch that is a part of this AC “knob”. It is probably defective. If you want to turn off the AC, disconnect the wires from this switch ---
**Author:** ![asheoran](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@asheoran](https://community.cartalk.com/u/asheoran)\ **Post date:** [October 12, 2007, 1:48am UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/3 "2007-10-12T01:48:49Z")
Thanks. I will take the wires off. If replacing the A/C switch can fix it, I will do that next summer. However, how can I know that the switch is defective? Can I replace the A/C switch with any of the other two switches (such as the rear windshield defroster switch or the outside/cabin air selection switch) to determine if the A/C switch is defective. Thank you for any suggestions. ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [October 12, 2007, 4:33pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/4 "2007-10-12T16:33:10Z")
Is it on defrost??? The Civic’s ALWAYS has the AC on when on defrost. ---
**Author:** ![asheoran](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@asheoran](https://community.cartalk.com/u/asheoran)\ **Post date:** [October 12, 2007, 5:24pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/5 "2007-10-12T17:24:47Z")
Thanks, I did not know this. However, the rear defrost is not on. I managed to turn it off yesterday for a second as when I changed the air selection to defog the windshield, It came back on again. ---
**Author:** ![asheoran](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@asheoran](https://community.cartalk.com/u/asheoran)\ **Post date:** [October 12, 2007, 7:45pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/6 "2007-10-12T19:45:25Z")
MikeInNH- You are right, it is on only when I turn the fan to defog (or defrost). That was an easy fix, and I thank you for the info. I was going to open it up this weekend, and I almost ordered the A/C switch as well. In our other car, Camry, I leave the air at defog/feet selection but A/C does not turn on. I do the same in Honda but now I will not. I do not like this function though as I was going to install remote starter for winters. What is the point of car running both the hot air (defrost) and the AC when AC is not needed. ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [October 12, 2007, 8:41pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/7 "2007-10-12T20:41:16Z")
You’re welcome. For some reason this is only the case with the Civics. The Accords don’t work that way. I have no idea why. ---
**Author:** ![Beadsandbeads](https://avatars.discourse-cdn.com/v4/letter/b/c57346/32.png) [@Beadsandbeads](https://community.cartalk.com/u/Beadsandbeads)\ **Post date:** [October 12, 2007, 11:15pm UTC](https://community.cartalk.com/t/a-c-of-the-car-civic-2002-lx-is-always-on/5813/8 "2007-10-12T23:15:53Z")
The AC comes on in the defrost/defog position because it dehumidifies the air as it cools it first running over the AC evaporator coils. It then gets warmed in the heater core producing very dry air. If the temp is low the AC will not operate anyway, just because of the physics of the system. It really is a good way of doing things for people that don’t understand what “dew point” means.