Well, the back right window in my 2003 Audi A4 3.0L Cabriolet is about to completely crap out. Since I got it about 8 months ago, it would, on a rare occasion, go up about half way and then back down when holding the up button. However, if triying again immediately, it would work as normal. That was not the case yesterday and I needed the assistance of a friend to vigorously pull the window up while I pressed the up button to get it up all the way. I tried getting a quick glimpse of the mechanism only to be greeted by the speaker assembly and not being able to get around that. I feel that it might be too intensive for me to attempt to fix it. However, what are some of the possibilities for this problem? Could it be a battery issue? The reason why I ask is because after attempting to get it up repeadetaly, I was forced to wait a bit at times in order for it to have enough juice. Also, my HomeLink buttons stopped working recently and my car alarm is having problems activating with the keys. Is there a way I can diagnose the battery for low power, damage, etc?

Thanks in advance...