I haven't had a change to test the charging system yet, so this is a preliminary peanut gallery roundup.

The red battery light came on yesterday about 20 mins into a normal heavy traffic commute. I turned on my bluetooth ODB app and noticed the voltage (reported as 'Control Module' voltage) was just below 12v and was slowly decreasing. Then the battery light went off and voltage returned to ~14.2v. Over the next 25 mins, the voltage dipped below 12v and returned to charging levels two or three times. I turned off all accessories that I could to reduce the rate of drain so I could get home.

Is this how a failing alternator behaves, or is a "it works or it doesn't work" sort of part? I'm going to check and clean battery terminal contacts, and check the battery charge itself later tonight when I get the time. Are there other parts worth investigating beside the alternator, battery, and terminal connectors? Or anything else that may be contributing to the problem?

Thanks.

 

Check the condition of the belt. A faulty alternator will give the problems you gave.
Do battery and alternator tests.

 

How old is the battery? If over 3 yrs, replace it.

 

I would replace the battery. But if you’re on a budget and want to eliminate another cause...get it load tested at an auto parts store to see if it’s an alternator causing the issue.

Remember to code/register the battery to your car or it’ll have a short lifespan!

 

Did what testing I could when I got home. Alternator has failed. Confirmed by the shop down the street where I dropped it off. I don't feel like struggling with this repair myself, as I've got a Jeep on jacks right now waiting for rear brake parts. Here's to spending an arm and a leg for what should be simple repairs! I'm selling this damn car as soon as I can.

Thanks folks!