I just bought my car a few months ago from a private seller. It's a 1999 Audi A4 2.8 quattro 5-speed. One problem I seem to have is that my battery wont stay charged. It wont start on the first try and all lights will be dim. Once I try and start it for the second try it will start but the battery light is on and interior/ exterior lights remain dim until I rev past 2000rpms then the battery light goes out and all the lights brighten. The guy that had it before me said he owned it for a year and it did the same thing for him and he couldn't figure out what was wrong with it. It drives fine once revved passed 2000rpms and I was fine with me having to start it on the second try until one day I went to start it and nothing would happen not even a clicking noise no lights nothing. I had it tested and it said it was my battery. So I put a new battery in it and went to start it and once again wouldn't start til the second try (battery light still on etc) once revved passed 2000rpms it was fine again. (the test said my alt and starter were fine)Then two days later it was dead again had AAA come jump me and they tried to run the test again but it wouldn't work because for some reason my radiator fan stays on after my car is off even tho its 10 degrees out. So i don't know if that could be whats draining it since I don't think the fan should always be one while driving and turn back on when the car is already off when its so cold out. Or if its the alternator or connections somewhere but no one can seem to see a problem with any of the connections and the battery is new. Now today while driving the battery volts indicator is moving from 10-15 when I stop it goes down to 10 so I rev and it goes back to 15. If anyone knows what could be wrong with it please let me know.

 

if i recall correctly, the relay on your radiator fan is sticking if it stays on even after you shut it off. do a search on that.


as far as the voltage fluctuations, knowing that the alternator checked out OK. Your serpentine tensioner is most likely losing its tension. I noticed the same symptoms last winter, and replaced my tensioner in the summer.

 

Thanks for the reply... I actually had my serpentine tensioner replaced last month but that hasn't helped. As far as the relay I have read about that and I'm guessing thats why it wont turn off but I thought maybe that was draining the battery also