whenever i use my heat, my battery volt goes down and things start to shut down. the car doesn't stop on me, but when i turn it off, i need a jump to restart. it seems to run ok during the day, but night time is a big problem, especially now that it is cold here. i'm in st. louis missouri.
i had the battery and alternator checked at autozone and was told nothing wrong with them.
please help. thank you.