Question re AC/Defrost

[nitt79]

As you know, when you turn the vent control to defrost the AC kicks on. When you try to turn off the AC in that setting the light on the AC button goes off but the AC remains on, is this the way its supposed to work? It seems like you should be able to turn off the AC in the winter time and use the heat if you want to. The dealer told me that its working like its supposed to, if thats the case, it's a stupid design. Its less fuel efficient and its puts more wear and tear on the AC.

[Blis]

Maybe so, but the point of the defroster is to remove the fog from your windshield, and that is what it is doing.

As you probably know, the "fog" is actually condensated water on the inside of the window, and the best way to remove it is to "dry" the air in the cabin a little bit and blow away the fog. As the air in the car gets drier, there is less fog.

What A/C does is that it removes the water from the air, making it drier (that is actually how it cools it down), which in turn will defrost your windshield much faster than using just hot or cold outside air. Trust me on this!

[FriendlyFocus]

Just turn it one notch up to the defrost/floor setting and leave off the AC. If you have it on full defrost it will always use the compressor but if you have the temp control turned onto hot it WILL be hot air. It will just be nice dry hot air. The way they have it designed works very well IMO

[Noyz01]

um, i noticed that there is no lack of power commonly found when the AC is on when i got the defroster on, kinda wierd....im just happy i have an AC! my old car didnt and i used to die literally in the summertime

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[nitt79]

Thanks for your comments, I realize that using the AC is the most effective way to defrost but you should still be able to turn it off if you want, because the windshield will usually defrost quickly with the AC. According to the manual the AC won't kick on below 40 degrees, so if chilly outside (40-50) you may want to warm up your car but not have heat blowing on your feet. Its a matter of choice, and I'm not offered this choice without compromising fuel efficiency and putting additional wear and tear on the compressor. My Accord doesn't work this way, what about other cars?

[JonBoy470]

Most American cars have the A/C tied to the defroster just as the Focus does. Virtually all A/C equipped GM and Ford cars that have a selector knob or slider but no separate "A/C" button do the same thing. The A/C comes on when you set the control to defrost. They just don't have an "A/C is on light"

As for wear and tear on the A/C, two points:

1. You got A/C to use it, didn't you?
2. Running the A/C regularly actually helps it last longer with less maintenance.

The R134-a regridgerant in the A/C acts as a lubricant and seal conditioner. Running the A/C for a few minutes every week or so (whether it needs to be running or not) keeps all the seals, hoses, etc in the A/C system nice and wet, so they are less apt to harden, rot, etc. and cause leaks which are expensive to fix.

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-Jon
2k ZX3, Infra-red, auto, air, cruise, tilt, pw/pl/pm, abs, var. int. wiper conversion, Sylvania XV headlights
IM: JonBoy470

[nitt79]

Yes, I've got the AC to use it, preferably only when I want to. I don't have a problem with the AC being interlocked with the defrost I just have a problem because I can't turn it off once its done defrosting, usually within 30 seconds. Are you suggesting thats its a good practice to drive with your AC on long trips (I do alot of highway driving)in the fall/winter and sacrifice about 5% in gas mileage. I don't, so I switch the setting to floor/windshield, something I'd rather not do if I had a choice. Recently, I've owned a toyota, honda, nissan, and a subaru and none worked this way. I guess its a USA/JAPAN thing. Are you all defending this as the best design, I guess we'll have to agree to disagree.