I just replaced mine in a 95 Aurora. Assuming nothing has changed too much between 95 and 98, remove the panel underneath the glove box (passenger side) and the fan is located closer to the engine than the seat. You should see the motor cylinder mounted to a larger mounting bracket. Only three screws on the mounting bracket need to be removed to get the whole assembly out. Make sure to disconnect the hose leading to the fan and keep it. My replacement motor did not come with that hose. In all it was a very easy thing to replace by myself and only cost $60.
