Reluctant Rad Fan

[kauffman@IMAP2.ASU.EDU]

Wow!  The list was on a tear today (yesterday, for some)... 7 digests! 
Shot a good two hours sifting through the lot.  Nice synopsis on the A8,
Eliot.  Thanks for the good reading. 

Now to add to the volume:

I've noticed that since we've had the '86 5OOO, the radiator fan won't run
if the ignition is off.  If the fan's running as the car is parked and the
engine is shut-off, the fan stops, and will restart only if the key is
turned on again (usually to close a window that's still open). 

It's been such a small issue that I've ignored it for the past 21 months. 
But now that it's officially summer again (strange, thought that was
earlier this month when it hit 111 F =) I'd like to track this problem
down.  As it is now, I feel guilty if I don't sit there and let the fan
cycle off after parking the car.  So what might be the problem / solution? 
The (Haynes) manual appears to say that the fan is _supposed_ to only get
ignition-switched power... NOT!  I need some help on this one! 

TIA

Karl K.      '79 Fox  144k mi
Mesa, AZ     '86 5OOOS  131k mi