John Eschberger wrote to the list:
The first 3 speeds of the A/C blower do not work. Additionally, if the blower switch is turned from 4 to any other speed, the compressor disengages. The good news is that the A/C blows COLD, but the fan on 4th speed (continuously) is too loud. Note also, the fan speed does seem to modulate if the temp setting is increased. The PO did have the A/C panel replaced, do you suppose that the mechanic didn't connect the wires correctly?
93 GTS 5 speed
As Jim Bailey pointed out, the lower fan speeds depend on current flow through the resistor pack, located in the air duct under the rain cover at
the base of the windscreen by the wiper motor.
Since the PO had replaced the dash controller, I'd start looking there. The wiring for the fan resistor exits the controller at the rear of the controller (this is towards the REAR of the car, closest to the mounting face of the controller in the dash) on the left side (driver's side on US cars.) If that connector is loose or not attached, you will experience the fan symptoms you describe.
To access the connector without pulling the controller, you can remove the lower carpeted cover on the driver's side of the console, and snake your hand up to see if the connector is seated tight on the controller. If you can't get in there that way, the controller can be removed through the face of the dash fairly easily:
Note that the wire harness lengths do not allow you to do the connectors
completely clear of the console; You'll still have your little fingers in
there getting them attached again.
Hope this helps!