They are behind the windshield wiper moter - or at least one of them
is.  Once you get the plastic drip tray guard out, you kind of feel
around up nd behind for a pair of 10mm nuts.  They're almost
impossible to see, but they're there.

It's attached with an allen screw in the bottom of the T handle, and
there are two side screws and one screw under the pop-out cover for
the drive selector. Once you get that screw out, be very careful when
pulling the console. It helps to get the seats all the way back, and
take off both accessory trays under the dash.  If you aren't careful,
you'll break off the little tab the inside screw goes through - it
tends to hook on the gear housing as it comes out.

Nope.  You need to take the car to a garage that services air
conditioning and have them empty your system. They'll deduct the
volume they take out from the recharge you put back.  If they're
willing to do it, have them loosen the two union nuts that attach the
air conditioning unit to the compressor - they're up against the
firewall on the passenger's side. They're made out of aluminum, and
are really easy to bugger up.  You want the little square block out of
there without buggered threads, or you're into the junkyard for a
replacement.

If you can, go to a junkyard and take another 85-92 with air
conditioning apart for practice. There are a lot of little clips and
stuff you'll have trouble finding when you put it all back together,
and a full set of spares is really nice to have. The little flapper
door that shuts off airflow to the floor in the defrost mode will
probably have one end broken off, which is why you haven't been able
to get it to shut off for the last 80,000 miles.

If you can afford it, buy a new heater fan and install it when you put
everything back together. There is no other fix for the early morning
wailing when you first start up cold.

I've done this repair twice on 85's (identical underneath). It's
difficult, time-consuming, and involves a lot of fiddling to get
everything back in place.  I'd advise taking a lot of pictures with a
digital camera as you take it apart so you have them to refer to when
you're trying to figure out how the Hell Wolfsburg managed to route
all those hoses.

Pat Moore
85 Jetta in Juneau, AK

VW time was just over 2 hours to replace the core when the recall was done.
Most of us VW techs were doing the core in 1 hour or less. That said here is
my don't list

1- don't need to remove the dash.
2- don't need to remove the AC box
3- don't need to discharge the AC