2002 Civic Heater/AC functionality

I have a 2002 Civic LX and am happy with this car with the exception of the
annoying Heater/AC functionality. It's cold here in Montreal and it bothers
me that the AC automatically turns on when front windshield defrost is
selected. Why does a car manufacturer force this functionality? The
salesman said it was made this way so that you get dry warm air. It's so
cold and dry in the winter here so that argument is not valid, why would you
need dryer air? I still purchases the car because it had many other features
but this one still annoys me and gives me the impression they just tried too
hard to cut corners.

Anyone know if this irrational functionality could be changed or fixed ?

 

I live in Montreal too. AC is very useful in defogging the windows when it
rains or when the temperature is below 0.
However, I agree that it is pretty useless at -30 C like this morning.
There is a way to modify/reduce this feature. The AC will still come on when
you turn on the fan in defrost position but you'll be able to turn the AC
off by pressing the AC button (while with the factory setting the AC button
has no effect when in defrost position).
I don't remember the exact sequence but I had it deprogrammed on the 2001
Civic I used to own and did it on my 2002 CR-V.
Someone here should be able to supply the sequence, if not you could find it
on the web.

 

The AC is on, but is it engaged? It will be engaged as the temperature
allows, but it won't be engaged when the temperature is low.

The goal of the defroster is to get the moisture off of the windshield.
When you breathe out, you blow warm moist air right at the windshield.
The absolutely most effective way to get rid of it is with warm dry air.
The heater makes the air warm, and the AC makes it DRY. That's the
whole purpose of AC, to dehumidify the air--not cool it.

If it's that cold, the AC won't actually engage. But the system is on
and ready for it to engage as you need it, as the temperature (and
humidity) rise.

You're worrying about a light being on, nothing more. Don't worry about
it.

How is this "cutting corners"?

 

Am I mistaken in thinking when set to defrost setting, even if the a/c light
is on, as you turn the temp dial to warm/hot you will in fact get warm air?
I have always understood it this way (at least on my vw.... have only had
my crv 24 hours now!). So if it's warm wx and the temp dial is on cool,
then the a/c is set by default, otherwise you get hot air as needed...

a

 

If you look around on www.7thgencivic.com you will find how to override
this. I have done this on my 2002 and it does override the A/C. I don't
think it has anything to do with cutting corners (I'm not even sure what you
mean by that). The A/C does help in defrosting in some circumstances when it
is warmer (40 - 60 deg f), but when it is 0 deg f, the A/C is pretty
useless.
There is more to it than just the light coming on. You can hear the load on
the engine with the light on vs. off, so it's either the A/C pump kicking in
or that is one energy sapping light on the A/C button.

Walt

 

Believe it or not, the salesman is actually telling the truth. The humidity
comes from your breathing. If your windshield is already clear, then it
probably won't make a difference whether AC is on or off, it can maintain a
clear windshield either way. But try this experiment: while parked in your
driveway (don't do this while driving!), turn off the defrost, and breathe
heavily to fog up the windows real good. Then turn on the defrost (without
AC) and see how long it takes to clear the windshield. Now try the same
experiment again, but turn on the AC. You'll notice that it defogs about
twice as fast with AC.

This point is invalid. It takes more effort to have the AC turn on
automatically with the defrost than to have the driver manually do it. If
they wanted to cut corners, then this "feature" would not exist. Even though
it annoys me, I can understand why the manufacturers (not just Honda) are
all doing this. It's because there's a lot of ignorant drivers out there who
don't understand how to properly defog their window. They've got the fan on
high, but in recirc without AC, wondering why their window keeps fogging up.
The manufacturers do this purely for safety reasons, and it takes them more
effort to do this.

Yes. Search in this newsgroup in google groups and you'll find the code
sequence. The AC will still turn on when you switch to defrost, but now
you'll be able to turn the AC off.

One way I was able to avoid turning on the AC at all was to switch to
defrost and turn off the AC *before* starting the car. Then after you start
the car, you'll have defrost without AC ever turning on.

 

At 0 degrees F, the AC isn't engaging. Trust me. If you doubt it, you
can open the hood and check for yourself.

 

Thanks for addressing this issue. I'm glad it's just an indicator light
that's "on" and the AC is not actually working, however what was annoying
was the passanger comments "It's -30 degrees Celsuis and you've got the AC
on". I re-programmed so the light is "off". You simply turn vent knobs
counter clockwise, hold A/C and recirculation buttons, keep holding, then
start your car and keep holding for 10 seconds until the lights stop
blinking. Do the same to revert to A/C light coming on automatically with
defrost.

I like to have have control over the AC and the AC light. I thought Honda
was trying to save a ventilation control by pre-selecting the AC light when
in defrost. A/C .

 

I would think that the AC pump would last longer if it occasionally gets some
exercise instead of staying dormant for an entire season.

Pars