So I know that this thread is old, but I figured I'd post here instead of staring a new thread.

I just competed this upgrade on my 2002 pontiac grand prix gt and the lesabre belt is very loose and sqeaks with new belt and tensioner. Should I try the stock belt?

Also, the battery light is on and throwing codes for alternator output, but I'm getting 14.2v output and battery is charging fine.

Any advice would be appreciated!