Not sure off the top of my head what the temp is for the "idiot light", but that info has been posted on this site. A search should find it. My light was always coming on even when it wasn't icy but very hardpacked. I know the rear heat exchanger was only about $44.00 + labor, but my dealer didn't end up charging me anything. I ride mostly groomed hardpacked trails up here so it was a must.