3.1.16) Why does the A/C come on when I use the defroster?
Description
This article is from the Toyota RAV4 FAQ, by Ralph Becker with numerous contributions by others.
3.1.16) Why does the A/C come on when I use the defroster?
It's supposed to. The owner's manual is specific about this feature.
The idea is that whenever you need the windshield cleared, the air
conditioner will come on to help get the job done. The A/C not only
provides cool air when it's hot outside, but it also dehumidifes the
air. Dehumidified air is much less likely to cause the windshield to
fog up. Many cars have this feature without their drivers even
knowing about it. Some people even contend that the primary purpose
of the A/C is to dehumidify the air, and cooling is a happy side
effect. In any case, if the conditioned air is too cold for you, just
add a little heat by sliding the temperature lever to the right a bit.
That said, use of the A/C does cause a reduction in both available
power and gas mileage. Most estimates I've seen are in the 10% range,
but this kind of drop is especially noticable in a vehicle like the
RAV4, with a small engine and relatively low horsepower. Some drivers
would prefer to have complete control over whether or when the A/C
comes on because of the penalties. The easiest way is to disable the
A/C in defrost mode is to move the control lever all the way to the
right (full defrost), then move it slightly to the left until the A/C
turns off.
Update: This "feature" was removed in the middle of the 1999 model
year. In the newest RAV4s, the A/C no longer comes on when the
defroster is engaged.
A more permanent way to disable the automatic A/C feature
requires a minor modification to the vehicle.
According to Mark in Vegas <ranyhyn@wizard.com>:
I just did it, probably took about 10 minutes. If your Rav is the
same as my '97, it's pretty straightforward. If you aren't
mechanically inclined, maybe have someone at a stereo shop do it for
you. Start with removing the fascade for the stereo, remove the two
phillips screws on the bottom of the fascade, there are two tabs on
the top that will come loose once you swing the bottom of the radio
fascade out. Then there are 4 phillips screws holding the radio in
place, two on the sides and two on the bottom. Remove those and pull
the radio out, if yours is like mine, it should pull out enough so
that you can get your hands in the opening and not have to pull any
radio wires loose. Anyway, take a look in the opening and you'll see
the bottom of the temperature control unit, on the back of this,
towards the center pointing down is a white plastic plug with a yellow
wire and a black wire with a blue stripe. There is a little tab on
the plug that you can push in and the plug will pull out (down). Do
this and voila, you can now control the A/C manually when in defrost.
If you want the A/C on to defrost the windshield, push the A/C button,
if not, don't push it.
A comment from another reader:
The wire colors have changed on my '99. Instead of yellow and
black/blue to the plug in the procedure, my colors were yellow
and white with a blue tracer.
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