For posterity, this a problem I am working now in my 98PA. Cold air flow restricted from the defrost vents and floor vents, with the fan blowing like crazy. No air from the dash vents no matter the air flow setting. Since there is a rubber tube that directs cooling air directly to the fan motor, it is not a good idea to try and use the HVAC with this condition.
I was doing that and suddenly smelled strong electrical smoke. The fan still works, but I may have damaged it.
I think there are four actuators, two on each side (left and right) of the HVAC housing. The "mode" actuator controls the air flow to the different vents. It is the one farthest from the firewall on the drivers side of the unit. Unfortunately it is a real bear to get out. The manual says to take the steering column out, and then the dash, even the aluminum support under all the plastic parts. The aluminum support is more or less moulded around the components to save space for the passenger compartment. I have cut an access hole in the support to see the actuator, because I didn't want to remove the column and dash.
The actuator is mounted very close to the support and you can easily cut the actuator unless you carefully use something like a Dremel to make shallow cuts. I realize that I am reducing the structural integrity and I may still need to remove the support.
The mode actuator has some complicated linkage that moves both the dash vent flaps and the door to direct air to the defrost in conjunction with each other. I may need to invest at Harbor Fright in one of those fiber optic scopes. This is the type of job that mechanics won't touch so you either do without cool and heat or do it yourself.
The other actuator on the drivers side is air temp mix. The two on the passengers side are air temp mix for the dual temp control, and the air inlet / recirculate actuator.
I did get the actuator out and it had the classic "split plastic gear" problem that keeps the actuator from moving the air doors. I replaced the gear with one from Ebay but re- installing the actuator and linkage may force the support removal. Story not complete yet.
The earlier PAs are not the same, the 1997 through 2005 are mostly alike.