There is a possibility that the battery cables are no longer good, or the Ground is bad also. So check those cables to see. Battery would show 14 plus volts when charged if not that could be the problem sometimes they are bad out of the box.
Also I am attaching a google link that has symptoms listed such as you have and maybe the fix is right there. you may find it.

https://www.google.com/search?source...60.dEXWkl2wHMQ

 

 

You need to get to the Battery they are usually covered up in these cars, mine is.
I have a side terminal battery.
I just replaced mine this summer.
The old one was still functional but I knew is was probably close. The battery Case had a bulge in it after I got it out.
I removed all the things blocking it ( windshield washer reservoir, engine bay cross member, probably the Air Cleaner too) etc.
Not sure of what year your car is. But most likely it is on the drivers side of the Car. Might be a Red small box above it for Jump starting the car too.
Check and clean the cables where they attach to the battery they make a metal brush for this work, remove the cables and clean each one.
Put the Red one back on first then the Black which is the ground cable.
Check those cables to make sure there are no cracks in them and at the end of the black one it should ground to the frame some place. Probably with a bolt attached. clean that as well. use the metal brush. Make sure that connection is tight. A friend of mine uses a little dremel tool, you can do it with a cordless drill also. Inspect the cables with a flash light to make sure they aren't cracked. If they are they are junk.
If the battery is 3 or more years old it will be weak anyway and may cause the light issue too.

 

 

Well these are the easy and cheap fixes. If it isn't that! Then you are looking at the Computer controls of the car. If you had a chance to review any of the google links I provided that is what they are indicating. So I am hoping this will not be the case. Tracking the stuff down can be a pain.

 

Did you ever get any resolution on this? Im having similar issues on my wife's Caddy, and all the cables have been checked and cleared, along with the alternator.