It started yesterday, I was on my way home from work with the AC on and suddenly a loud whine started. I turned the AC off but the whine was still there as long as the fan was on. Once I turned off the fan the whine went away. This morning I just turned on the fan without the AC and the whine started up again.

There doesn't seem to be any problem with the engine. The AC also seems to work fine. The whine only occurs when I turn on the fan. Has anyone else had this problem and is there an inexpensive solution? OH, by the way I have an '05 XF coupe.