Hello,

2008 G37 with about 160k miles

I just turned my car on and the battery light was on. I sat there a few minutes, revved the motor a bit and it didn't turn off. Then the VDC OFF light turned on, then slip. I shut the car off. After a minute I turned it on again, same thing but faster. The ABS light also came on. Then the entire gauge cluster went dark for a second and came back. I shut the car off not sure if leaving it on would screw something up if water got inside or something.

I drove it earlier today, not a single issue. Could the alternator be dead? Would it happen that suddenly?

It is raining. I looked under the battery cover and there is a little water on some wires. It's been raining for a few days though, no problems.

Tomorrow when it is light out, I'll start it up and check the voltage...

Any ideas before then?

Edit: The dust cover under the car has a hole cut in it since it was damaged and hanging off. I was driving in the rain earlier. Could water have splashed onto the alternator while I was driving, and caused it to have problems next time I started the car hours later once it was cold again?

 

Update: I couldn't wait so I just reconnected the battery and started it. It started, no lights except the battery light at first. I checked the voltage at the battery, it was under 12v. Got back in the car and all the other lights were back on again.

In any other car I would say it is the alternator, but don't these cars have some kind of voltage regulator or something?

I don't want to disconnect the battery while the car is running. Again, I used to do that all the time on older cars, but I don't want to burn out any electronics by doing that on this car.

 

I just swapped the alternator, changed the serpentine belt while I was at it. I noticed the old alternator was completely covered in power steering fluid, my reservoir hose has been slowly leaking for a few years now. I think that may have damaged or destroyed the alternator. Anyway, after putting a new OEM alternator in, and I had to jump start the car, my voltage was back up just under 15v and the car runs perfectly now.

It may be my imagination, but it feels like it is running smoother with more power, idle is steady and smooth too. Could just be my imagination though...