Hey guys I'm finally putting in a Pioneer CD player in my 05 sierra. The guy at Best Buy said something to me about how all the warning/alert chimes, and sounds are run through the head unit and without this $120 harness I would lose the warning sounds. He said this happens on the 03 and up GMC's. Is this true? I figured that there has to be a way to get around all that with using the regular harness they sell for $15. Can anyone help?