The fan set at high sounds like it fluxuates in speed, but the air flow seems to be the same? Have had checked at dealer. They replaced fan, but still have the problem! They do not know what is wrong. About 4 months ago the alternator went out and was replaced, but the fan problem was later than that. Noticed the digital clock on rare occasion goes out for a second or two. Not sure if that is important in the diagnosis?