Hi I have a 1999 Ford Festiva, every time I use the A/C or demister my battery goes flat. I was told that it was my alternator, but I find that hard to believe as it charges the battery fine as long as the A/C and demister are not used. I can even have my Cd player on without the car running for ages and the battery is still fine. I was wondering if you can please give me any clues to what it could be. Maybe a loose wire and if so where would I find it? Thank you.
you need to check the charging rate on the alternator as it may be charging low