Wipers, etc on 4000q

["Guillermo S. Christensen" <gchriste@cap.gwu.edu>]

Three assorted questions related to my '84 4000Q (a recent purchase).

The wipers on my 4000Q sweep more slowly than those of most cars I have
driven., and I am wondering if this is normal.  On the high speed setting,
they wipe the windshield at about the same rate as most other cars' slow
speed.  I looked in the Bentley manual but there is no troubleshooting
info on wipers.  Is this most likely a problem with the wiper motor (or
would it just quit working if it was kaput?) or with the linkage, or
something else? 

On a different matter, the outside mirrors are supposed to be heated when
the rear defroster is turned on.  The driver's side unit on my car
functions, but not the passenger side one.  I checked the fuse box but
could not find any fuse specifically marked for the heated mirrors.  I
popped the mirror glass out per the Bentley manual instructions and
checked the electrical connections and they look OK.  Normally I wouldn't
much care about this, but with winter coming, it would be nice not to have
to scrape off one mirror when driving in snow or icy rain. 

Lastly, I would be interested in knowing from other 4000q owners as to what
kind of highway mileage I should expect to get?  

Thanks in advance.

Guillermo.