help!! Where's my fan switch?

[0022rel@informns.k12.mn.us (Jan Rootham)]

My radiator fan on my '86 5000cs quit working. With spring slowing coming to
the northland (MN) I'll need to get it fixed quickly.  I tested the fan
motor with 12 volts directly on the contacts and it ran (although loudly,
which isn't unusual).  So is the problem in the switch?  And if so where is
it located.  I called German Auto Parts in CA and they wondered if it was a
2 prong or three prong switch?? Where exactly is this switch located...I saw
a couple possibilities on the water inlets or outlets on the block.  One was
up high, the other lower (perhaps half way down) on the block. Is it easy to
remove and replace?  
Thanks

Jan    0022rel@informns.k12.mn.us