I would expect a broken vac line or return spring on the vac motor
that runs the doors.  There are several motors that work as a team.
Don't have a 2004 diagram and I doubt the 93ZJ will be close.

I have a 05 TJ that had similar issues.

If you look under the forward console where it blows from the lower
vent directly at the driver foot, there is a flap that is "easily"
disjointed from its hinges, even a slight kick can dislodge the
directional blade.  See if you can move it back and forth freely.
Mine was actually off the hinges.  It is a real PITA to get back on as
you must have very small hands to get it back in, in fact you must
also be a contortionist.  I had to have my son do it.  I'm to big, and
I'm not a big guy.

Also there is a vacuum line in that same vicinity, make sure it is
connected.  I let my son play in my jeep, and he must have pulled it
out and banged the directional flap.  It is farily obvious to spot.

Hope this helps.  Take care,

Ping me and I will send you a scanned copy of the O&M for which you are
having issues with.

Coasty