Hyundai-Kia Charging (or lack of) problems and one fix I discovered
I had the same problem as you all did. I wasn't getting any charge to the alternator and the alternator/Amp/battery light was on. Client changed her alternator three times and went through two batteries. All the text that she took the car to couldn't find the problem. What I did first, was check the output at the alternator. I cannot say for certain, (I would like if anyone can chime in to confirm this) but if the alternator isn't getting a requirement for output, it may not put out. I installed an alternator in one of my clients Kia Optima vehicles, and looking at the specs sheet that came with the alternator, it's not ‘scheduled’ to start putting out voltage until it reaches 900 RPM. I really hope that is a misprint! So, if that is the factory specs, that's something we as Hyundai and Kia owners should be aware of. With that being said, you have to check the wiring for voltage and continuity from the BA terminal up to the fusible link where it connects. You then have to take it apart, if need be, to make sure that the invisible portion of the connection you cannot see is not crowded with corrosion, as mine was.
Now for the good part: what I did was check continuity through the fusible link and found that the fusible link itself was the problem. What I did first was checked for voltage drop from the BU terminal of the alternator to the negative post of the battery itself, and found that the output went from 12 V up to over 14. That led me to believe there's something in the middle, and since I already checked the wiring, the fusible link or something around it, had to have been the issue . Take a look at the pics for yourselves and let me know your thoughts.
The part where the post goes into the fusible link was slightly loose so upon twisting it and looking at it more, I noticed that the plastic around it was global which tells me it melted from the inside. What would cause that to happen? Overload? Probably a bad alternator originally and someone tried to connect jumper cables to put them on wrong? In my case, this is a 150 amp fusible link and the one that's supposed to come with the car is 120 A, so connecting jumper cables even for a second could've started to melt but not fry that fusible link but the plastic and metal around it instead.
I think this client might have gotten a fusible link based on information that she gave to the dealership. Unfortunately, the fusible link average size was too high and I think that was melting the wiring. I'm not an electrical expert, so hopefully someone can chime in and help me understand this. But I did find the problem and I hope this helps everyone associated with Kia and Hyundai