Also one thing I forgot to mention was the alternator (Hyundai OEM)
was replaced at 70k, some 50k miles ago so it looks like it is too
early for that to be the problem.

Nick

Nick,

After you clean the battery terminals, it is a good idea to smear them
with a light coating of battery terminal grease that you can obtain at
most auto parts stores or you can make your own by mixing baking soda
with a medium weight grease (1/3 b soda + 2/3 grease) if you wish.  Then
put the connectors on the battery, tighten them up and smear more grease
over all metal parts.

I use this grease when I install a new battery and no more corrosion on
the terminals for at least 2 or 3 years.

Larry

It might also be a good idea to take both the terminals off and make sure
the contact areas are clean as well.  

It's also a good idea to perform a basic starting and charging system
check.  If your air bag lamp is coming on, you should suspect that your
alternator may not be charging.

Thanks for the advice Larry, I will give it a try and clean the
contacts as well while I'm at it.

Hyundaitech,

    The last time I replaced the alernator the battery light
actually never came on. 50k miles is a little short for the alternator
to be bad don't you think? Also she hasn't had any difficulty starting
the car so that battery is being charged (at least for now).

Thanks,
Nick

-------------- YOU'RE LUCKY TO EVEN ACCESS YOUR TERMINALS!   -------

I HAVE A 2004 ELANTRA GLS, AND THE BATTERY IS almost impossible to
replace and service!

Hyundai DOESN'T want you even try to:

1)   Check the fluid level in the cells.

2)   Check the body and terminals for corrosion.

3)   Remove the old battery and install a new one.

These tasks are almost impossible for the average motorist BECAUSE THE
BATTERY SITS IN AN ENCLOSED, SEALED CASE!   You can't see much less
inspect the cell fluid levels.  And half of the bolts under the hood
on the driver's side have to be removed to free-up the battery.

See, Hyundai wants you to go to a HYUNDAI DEALER, where a battery
costs $90, plus up to $50 more to install it. And at most Hyundai
dealers I know, you have to leave your car for an entire day -- then
hope it's ready when you return in the late afternoon or early
evening.

"Aw, we're sorry, but you see we got real busy and couldn't get to
yours.  But tomorrow!"

AdvanceAuto Parts, AutoZone, Olympic Auto Parts, and Batteries Plus
sell the same battery for $52 to $69, some including free
installation.

Only problem?  They can't get a sufficient supply of them to keep 'em
in stock!

And that's what your conniving, inscrutable Hyundai folks want -- to
force you to spend more on a new battery than a normal car owner would
expect.  Parts companies list the Elantra batteries as "special."  And
that they are!

Additionally, the OWNER'S MANUAL has neither a diagram or instructions
for accessing and servicing your Hyundai Elantra battery.  Just a one-
paragraph entry that says, in effect, Be careful when servicing the
battery."

I've had my 2004 Elantra GLS for 3 years and the battery is already
shot.  Needless to say, with problems also with the air bags, brakes,
power locks, and engine noise and vibration, I've bought my last
Hyundai product!

My advice to Hyundai?  Hold up on building those factories in the
U.S.  Too many one-time customers could make for sluggish, then
anemic, sales.

------------------------