Robert,

I've added factory a/c to my 87 so I'm pretty familiar with both
wiring setups.  Bentley is hard to follow but it is all in there if
you really search.  The two systems are different - a lot different.

Basically your fan should work fine if you haven't done anything to
that wiring.  I would strongly suspect that your fan resistor is to
blame.  It's a very common failure item.  It's located behind the
driver's side headlight - I would start there.

After that there are three relays that run your fan - I would find the
70amp unit (stage 3) and try jumping it.  That will run your fan at
top speed (a speed it should rarely hit).  Or maybe try jumping things
on the rad. thermoswitch.

You're welcome to mail me off-list if you'd like to brainstorm on it..

Damian