Lights and headlights

Hi All,

Two questions relating to my 2001 Hyundai Elantra:

1) A couple of bulbs have burned out on the instrument cluster. I'm
having trouble replacing the two smaller lights that went out (fuel
gauge backlight and transmission gear indicator - drive): They're
teenie tiny bulbs - 3/16" in diameter, about 1 millimeter smaller than
a size 37 bulb. I could not get the 37 into the twist-lock socket. Is
there some other size I should be looking for? I swear I spent an hour
looking through hmaservice.com and could not find bulb size
specifications for instrument panel bulbs.

2) I have had my left headlight burn out 3 times in about a year and a
half. It's starting to be a noticeable cost. What might cause one
headlight to burn out frequently?

Thanks!
-Matthew

 

1) Not all the cluster bulbs are the same. You should be able to source
bulb and socket assemblies from the dealer. Expect to special order
them.

2) -- cracks allowing water to intrude and contact the bulb
-- touching the bulb glass during installation
-- poor quality bulb

 

My 2001 Elantra had the same problems, constantly burned out headlights and
other bulbs, heard it was from an overcharging alternator. My daughter had
an accident in the car, she was stopped for trafiic, and a SUV hit her from
behind at 70MPH, drove her into the stopped car in front of her, big impact
to the front also. Air bags did not deploy, none of them. The car had a
history of airbag light being on, in the shop 7 times, said they finally
fixed it, but I also heard this problem could also be an overcharging
alternator affecting the airbag control unit.

 

Too soon to tell yet, but I'm beginning to think it might be a loose contact
to the bulb. I put some conductive greese on my contacts before plugging
the bulb in as I noticed the contacts seemed a little loose last time I had
a bulb go bad. So far so good, time will tell. BTW a bad alternator is not
going to burn out the left headlight 3 times and leave the right headlight
alone.

Dan

 

1) I realize there are different sizes... The largest bulbs seem to be
standard 168s, so I was hoping the smaller bulbs would be something
standard too. Alas, a special order! That's a bummer.

2) a) no cracks, maybe a seal is worn? I'll have to look more closely
next time it rains. b) I'm extremely careful to never touch the bulb
c) I've always gotten sylvanias; I haven't seen anything that would
indicate them being of inferior quality.

 

It is possible for one side lamp to burn out more quickly than another side.
If the length of the conductors
to the lamps differ there will be different voltage drops in the cables
leaving different voltages at the lamps.
Particularly noticeable on older 6 volt systems because of higher currents.
Once the rated voltage at tle lamp is exceeded
there is a exponential drop in lamp life. An extra 1/2 volt will kill a lamp
very quickly.See if you can get a voltmeter/multimeter to check lamp voltage
and alternator output.
Good luck
John

 

Elantras tend to eat headlight bulbs with 6 months being pretty typical
life, depending on usage. I'm on my forth brand of bulbs and so far
haven't found any that last longer than 6 months. It may just be
something inherent in H7 bulbs.

The fact that only one of yours is burning out is likely to be
coincidence. Next time, replace both of them with the same type and see
what happens. I'll bet they both burn out in about the same time.

BTW Osram-Sylvania bulbs are nothing special these days, though I've
heard that if you can find original Osram bulbs, they're better. Their
Silverstar bulbs are nice and bright, but have the shortest lifespan of
the bulbs I've tried so far. I've also tried PIAA, which were expensive
and short-lived. I'm currently running Hella lamps, but they haven't hit
the six month point yet, so I can't report on their durability compared
to the others.

 

In principle I agree, but once you replace a burned out bulb, now you have
an after-market bulb. Once you put those in, you may find yourself doing it
frequently, especially if the alternator voltage is high.

In my world, I would just hope that the one on the other side doesn't burn
out. OTOH, if it does, he should know quickly whether it is that problem or
not, as now both bulbs will burn out with annoying frequency. It just
doesn't seem to take much to burn out those H7's. Which might explain why
they are quickly being phased out as models are being updated.

 

My girlfriend has a 2004 Elantra with a similar problem. The stoc
headlights lasted about 3 years, then I replaced them with silverstar
when one burned-out. One silverstar buned-out about 2 months later, an
I thought it was a bad bulb. Wiothin a week, before we got around t
replacing it, she was driving to work in the dark and the other sid
burned-out. Well, We replaced those with Sylvania Cool Blues (I hav
used the H2's with no problem on my Subaru). Those lasted about a yea
now and one has burned-out again

The Hyundai dealer told her it was because the lights are always on
but I believe he was full of it because it doesn't have daytime runnin
lamps, and even if it did, that would be the high-beams. Do they sta
on when you turn off the car for a while though? I'll ask her, but sh
might not have noticed. Maybe the lower voltage in that case has a ba
effect

I want to check the voltage like John suggested - can someone tell m
what operating voltage I should look for? Can I just check at th
battery terminals for alternator voltage, since the system voltag
shouldn't be any higher downstram from that? I'm not all that familia
with the engine compartment layout in her car

Jaso

 

He IS full of it, as the headlights are only on if you turn them on.

 

You can verify proper alternator output by measuring the voltage at the
battery, should be in the 13.5 to 14.8 volt range or so. You can measure
the voltage at the headlight bulbs, but that will be almost the same
provided there is nothing wrong with the cars wiring, and that is the issue
here...these cars are burning out a lot of H7 bulbs when there is nothing
"wrong". I'm still sticking to the theory that the crimp connectors that
the bulbs connect to get loose after a bulb replacement or two and that is
causing problems (my bulbs are still working after using conductive greese
on those connections), but another thought has come up: when you leave the
headlights on all the time (as I and my wife do) perhaps a surge is going
through the headlights when the car first starts, or perhaps a surge is
generated when the car is turned off. I don't have the test equipment
necessary to test this theory out. One way to do it would be to train
yourself to always turn the lights off before stopping the car and then turn
them on after you start...but its sooo much easier just to leave them on all
the time...

Dan

 

I also had the same problems, see earlier post. On several occasions when a
headlight would burn out, the check engine light would come on.

 

True, the problem seems to be widespread on vehicles with no obvious
electrical problems. My car runs great and there are no obvious voltage
fluctuations. An unstable electrical system would likely wreak havoc on
the computers in the car, too.

If you're referring to "dielectric grease", it's NON-conductive
(http://www.merriam-webster.com/dictionary/dielectric). If the issue was
conductivity, the grease would gain you nothing and possibly make the
problem worse. This is a common misconception, probably due to the use
of dielectric grease on connections as a corrosion inhibitor. In that
role, it can reduce long-term degradation of electrical connections, but
it still does not increase conductivity.

That's a reasonable possibility, but my own experience indicates that it
may not be the problem.

I've tried that and it hasn't seemed to increase the life of the bulbs
at all. Granted, my experimentation with this has be limited and not
very scientific.

 

That seems pretty odd and may indicate a more serious problem. The only
indication I've seen of burned out headlights is that it's darker in
front of the car at night. ;-)

 

Light bulbs should last many years in these cars.
If they are exhibiting short life, there is a problem in th
electrical system. Duh

If the measured voltage seems to be in the correct range, it may b
possible that voltage spikes are present and these are taking out th
bulbs.

Has anyone tried putting a capacitor across the bulbs to see if i
helped? Depending on the length of the voltage spike, the capacito
may help. I would guess around 50-100 microfarads would absorb
short spike or better yet also parallel a smaller capacitor, sa
0.1-1 microfarad. Be sure to use a capacitor rated at least 25 volt
DC

This is just a thought but maybe worth a try. The battery will als
help with the spikes

Good Luck...Luk

 

Do you own one? It's a common problem with these cars, but it may be
more related to the H7 bulbs than to the cars themselves. My
understanding is that Hyundai has switched to a different type of bulb
in current models.

A few people on other forums have tried that and it hasn't helped.

 

My 2001 Elantra burned out the following items:

Headlights 4
Transmission Sensors 2
Air Bag Control 2

 

Wow, that's quite a coincidence -- my 2001 Elantra has also burned out
4 headlights (3 left, 1 right), two transmission sensors, and an O2
sensor, between 68k miles when I bought it and 118k.

 

The headlights don't surprise me at all, but the other items may
indicate a significant electrical problem. Has anyone checked your
alternator output?

 

My 2002 Sonata has H7 bulbs and it has never burne
one out and my wife burns them practically all the time. I suspec
this bulb short life is another one of those Hyundai problems tha
they will never fix

Have a couple of other things to try that I used to do when I designe
incandescent lights into products. One thing that adds life is t
reduce the thermal shock when first turned on. Installing a resisto
in parallel with the light switch will cause the filament to warm u
when the ignition switch is turned on. This reduces the therma
shock when the light switch is closed. I would try around 10 ohms
30 watt resistor. On the Sonata, the lights change to parking light
when the ignition switch is off and the light switch is on. I a
assuming the Elantra does the same thing

Another trick I used to add life was adding a very small resistor i
series with the lamp. A small reduction of voltage on the bulb wil
add many hours of life to the bulb. This value will be probabl
around 0.1 ohm, 2 watt. You will not notice dimming from this

These may be a little work to install but may be worth the effort

I still think the problem is caused by high voltage at the bulbs
either all the time or intermittently. This is the cause of th
failures