So let me preface this by saying that I bought the car used with 30k miles on it. At 35k miles I had to replace the alternator. I am sure the garage used aftermarket parts but it was a brand new alternator. I have had the car for about 6 years and it currently has about 108k miles on it. Ever since I replaced the alternator the battery light would randomly come on. I would tap the gas or breaks, the battery light would go off. I once let the car coast without touching the brakes or gas just to see if it would eventually turn off and it did, eventually. There is no rhyme or reason to when the battery light would come on. I can drive it for a week and have it happen 3 times a day, 3 times per trip, or a month without incident. I have found that it happens the most when I am coasting, never when accelerating, and sometimes when I break.
I have taken it into a shop now 4 times in the last 6 years. Every time its exactly the same: the battery is fully charged, the alternator is putting out correct voltage and amperage. Nothing seems to be wrong with the car itself. I will say that when the compressor is running my head lights tend to pulse. They will rapidly get dimmer and brighter in a cycle of about a 1/4 second. It is just enough to notice and I don’t think it has to do with the battery problem but it might so I mention it.
Is this even worth worrying about? What should I ask for next?
Thanks for the help,