Got a 2010 Elantra with 210k miles on Its been a well kept as the the carfax records show. Its from the south. No rust. Always had clean oil. Regular maintenance stuff.

The alternator died so I swapped it out in the closest parking lot I was able to drag it into without power steering. When I did the swap everything was fine. I never bothered to clear the codes after the alternator went bad. I knew it always had a check engine light due to a dead 02 sensor so I never bothered to scan for codes again after installing a new alternator. I saw it always had a code for the alternator once the first one died, and the 02 sensor code, and codes for it running lean before I just unplugged the bad 02 sensor.

Months after installing the new alternator the battery kept dying. I figured it was just an old battery. I would jump it, drive it around, and it would get a few cranks till it needed jumped again. One day it just wouldnt hold a charge anymore so I put in a new one.

I was curious to see what codes were still popping up after the battery died and there was no juice to the system for about 5-6 hours. I see the one for my unplugged 02 sensor which I don't really care about currently. I see one for high voltage on the alternator. I took it to the parts store that sold me the alternator. He said there was a high voltage reading like my scanner tool said. I asked him if the alternator is bad he told me id have to take it out and let them test it. I didnt have time so I left.

I asked what else might be wrong if the alternator is good. He said something about the wire harness to it. Said the plug that the alternator connects into might be broken. He said something about fixing it with a bobby pin O_o

Not sure. I'm going to be giving the car to my dad once I fix it. If the alternator is good, and the battery is fine, I want to fix this other issue myself. I know there is a voltage regulator somewhere that may need replaced and of course this plug that might be broken that the alternator connects into.

I wont lie. When I was replacing the alternator in the parking lot it was cold out and my hands were getting numb. My girlfriends dad was helping try to unplug the alternator and he got it off. I doubt either one of us were all that careful with it. If someone did damage the plug...what kinda labor am I looking at doing myself to fix it?

 

You are faced with an electrical problem you are not equipped to deal with.

You need a multi meter and how to use it , just for starters. You also need to know just how the system works so you can run the tests

This is really out of your reach and should be left to a qualified shop/person to handle it. I am trying to be honest and prevent you from getting into problems you are not equipped to handle.Please try to understand , I am trying to save you some $$$ and grief. If you want to learn to help yourself, get a few good training manuals and read and understand the info.
The voltage regulator is contained in the alternator, that is why you cant find it.
Electrical work is not difficult, but you need a good foundation to understand what is going on. For now , I suggest you consider having it repaired by a qualified shop.

 

I understand you. Diagnosing and troubleshooting isn't beyond my ability. I can grab a multimeter and check voltages. This elantra is pretty much just a spare car now. Ive been waiting to have one I can learn from when something breaks.

I've been a self taught computer repair tech and diagnosing/troubleshooting is something I just do with everything I get that's broken.

I figured it's a bad alternator. I know the voltage regulator is in it. I havent tried fixing this issue or looking for anything broken yet.

I figure the only components that worked before the alternator swap that now might have been damaged after the swap is the pins in the connector for the alternator. Which is one failure the guy at the parts shop told me can break.

I'm not afraid to try and find the problem myself. Depending on what the fix is, I'm probably not going to fix it myself.

 

You have the equip, and desire to find the problem . If we can offer any suggestions , let us know.

We don't know what you have to work with so must be careful not to direct you into a rabbit hole or where you might run into problems.

Believe you will find the problem, since it seems you are on the right path, thanks.