Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
Yes, there has been a service bulletin on them. It is in the top of the heater/ac box.
Remove or Disconnect
Install or Connect
File In Section: 1 - HVAC
Bulletin No.: 66-11-03
Date: July, 1996
Subject: HVAC Fan Only Operates on High Speed (Replace Blower Motor Resistor Assembly)
Some owners may comment that the HVAC fan will operate only on high speed setting.
The blower motor resistor fails open.
Replace blower motor resistor assembly with new part,