| I'm not sure if you'll even want to answer this, but here goes.
| I really dislike the fact that the A/C in my '04 Elantra is
| the defroster so that the they always come on together. I've
| rumor that this is a new federally mandated setup, but frankly,
| really sucks if you live in a cold environment and need maximum
| clear snow and ice from the windshield. On '03 and older cars,
| simple matter of snipping one signal wire to decouple them, but
| able to turn on the A/C manually with the defroster if you want
I agree with you. This was one on the list of engineering
stupidities of my late Ford Aerostar, which has met its just
reward after passing through purgatory. This design sticks in my
craw (and I don't even know what a "craw" is). And I don't even
live in a cold climate. My 2000 Sonata's heat comes up nice and
quick, but if I lived where it's cold, I'd want a whole lot
The other thing that gets me is that carmakers have been making
"always-on" heater cores, with the output controlled only by a
big air flap. In my experience, these tend to leak hot air into
the interior on a hot day. I'm not certain that my Sonata is set
up this way -- I haven't owned the car long enough to
investigate. It's an old practice, though: it was a "feature" of
my 66 Plymouth. I can't understand why they didn't use the
old-time idea of just putting a water valve in the hot water
line. These flap air deflectors leak in two ways, often both at
- They radiate from the heater housing, which is usually black to
help transmit the heat.
- The flaps often don't seal very well, either due to internal
leakage past the flap, or from wear in the vacuum activators, or
even perhaps a little vacuum leak in the tubing or controls.
The result is sometimes hot air blown on your face whenever you
want heat on your toes.
So, I've often wondered about the practicality of just putting a
water valve in one of the heater hoses to shut off the heat
totally in the summer. Or, is there some reason why the engine or
emissions will be harmed if the coolant isn't circulated through
the heater at all thimes?