Hey I have a 2002 hyundai sonata gls w/ 2.7

I have been having battery/altenator/electrical problems.

battery going dead, dash lights flickering on/off, headlights dimming and flickering, and car not starting. if i put the battery on a charger the car will start, and my battery terminals are curode I have to clean them at least twice a week (oh and autozone said my battery is good and will not replace it although i have a free replacement warrenty, the battery is 2 years old).

It all started about 6 months ago i was having the same problems so i took it into the shop and they said that my altenator was not charging my battery and the altenator was bad. They also related my badly coroded battery terminals on this. so they replace my altenator and cleaned the battery terminals. well the same problem still persist so i take my old alternator to autozone and have it tested. they say it is good.. ?????? so i replace the battery cable ends and the problem stops for 6 months or so.... well now i having the same problem again. battery going dead, dash lights flickering on/off, headlights dimming and flickering, and car not starting. if i put the battery on a charger the car will start, and my battery terminals are once again slowly starting to curode.

Somebody please get me out of this nightmare...

I have a Hyundai accent 1999 GSi and I have the same issue. I have had it for about 3 months now. First the power wire to my alternator came loose so we fixed it ourselves. I continued to drive it. It came loose again because we didnt do a good enough job. My battery kept dying, so i realised we had wrecked the alternator. So i finally took it to a shop, they said it was the alternator. They replaced it. This is when i realised the lights. They go really bright, and then they go dim. And then continue to do that the whole time im driving. Since this issue i have brought my car to the garage 3 times. Its still there as I speak and the mechanic is trying to figure out the issue. After i took it back the second time. He fixed a ground on the engine block that burned out 2 more alternators. He thought it fixed it there but it still isn't working properly. He is changing the posts to the battery, and he changed the alternator power wire connector and soddered it. So im just hoping whatever he does next fixed the issue, Its quite a headahce eh lol

let me know how it turns out and what the fix is if your gets fixed....
thanks

Dear v1xx,

The headlights shining brighter and then dimmer, brighter and the dimmer, is a classic sympton of a bad voltage regulator. This is mounted on a replaceable 'potted' assembly that mounts to the back of the alternator.

For Tony,

Did Autozone do a full load test on your alternator? Not sure if you have to take it out for this test, but they definitely can test it on the bench in most Autozones and run the alternator through about a 5 minute test cycle under varying loads.

I had electrical problems with my 2001 Sonata. New cable connectors fixed the problem. Check out that little cheap brass angle connector on the end of your cables at the battery. The Autozone tech said this is a common problem, cut off that cheap connector, installed a standard clamping connector, cleaned the terminals, and no problems in two years. Cost = $1.79 x 2.

Byron

I notice my lights doing the same randomly but i dont have the corrosion issue. I think most of mine has to do with my automatic climate control and the fact that im pushing almost 500 watts from my amp. definitley change your terminal connectors though...

I am having the same problem right now with my 02 sonata gl 2.4
I have a what looks like a 120A fuse on the positive battery lead.
Could this be blown? And could this cause my problems? I haven't checked it with my meter yet...

There are a few common problems with these cars, and this is one of them. Here is how I fixed mine.

1. Replaced alternator with a high amp version. Didn't really need to do this at the time, but I run a stereo system in my car and didn't want issues later.

2. Upgraded wire gauge from alternator to battery. Switched to a 1 AWG power wire to deliver more power to the battery.

3. Custom made a grounding system with 0 AWG as the main ground and 6 AWG to all ground points. This solved most of my dimming issues and makes the car run much smoother. Or you can buy a "Rare Earth" kit or whatever they call it on FeeBay.

4. Upgraded battery terminals and posts to gold coated high end car stereo terminals. No more corrosion! The stock terminals are crap and will always corrode no matter how much you use that terminal paint.

5. Optima Yellow top battery. A Red top will do, but like I said, I run stereo equipment.

Costs a few hundred dollars the way I did it, but it works great now.