Judy, it "might" be the belt tensioner after all. When you turn on the A/C more load is put on the belt to turn the compressor and that could cause the bearings in the tensioner to howl a bit. I had a similar problem on a Tahoe and changing the tensioner fixed it. I also don't understand waiting until the warranty expires. Right now, under the original warranty, it should be fixed at no cost to you. Why wait?
Last edited by UncleJ; 12-15-2007 at 10:12 AM.