Source for V8 relay

["Lewis Schnaper." <lewis@ukpik.com>]

Hi.  I need to find a used mirror memory control unit (4A0907445A) for a
'92 V8.  Everything else checks out in the remote mirror system, so....
I'd appreciate suggestions as to where to start looking.  

I also discovered that my LH mirror was replaced sometime in the past
with one that doesn't have the heating element, which isn't so good here
in Alaska.  Anyone in a warm place have a spare heated mirror that they
want to swap for the unheated version or, more realistically, what's a
good source for these.

Thanks.

Lewis Schnaper