2005 Trail Blazer Alternator Problem?

Hello Everyone. I have a 2005 TBlazer that has developed a whine in the alternator area. It is definately an rpm driven noise. I thought it was the alternator due to the recent headlamp dimming with alt
gauge showing a quick drop in charge rate and then recovery. My dealer seems to think it is my idler. I don't see the connection between the idler and short discharge though. I have a $100 deductable on my warranty, but they say the idler fix is under the $100. R and R of the idler looks pretty straight forward to me, so I'm looking to handle that myself if it is truly the issue. I can change out the Alt, but they are $168.. I'll let the shop do that one. Any ideas what might be going on here? Any help is appreciated. Thanks.
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wrote:

Make a listening device with a screwdriver and a funnel and see if you can better tell where the whine is coming from. Either can make that sound as the bearings are starting to go.
As for the alternator, look for a local rebuild shop. There are some small shops that do alternators, starters and such and often do them at very low prices since you are dealing direct. I used to have one where I lived before and it would be ready often while you waited or only a few hours later. Cash helps at those places too.
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