There are various flaps that open and close within the system to control air flow. Each flap should have its own motor.
If you take the glove box out and the top coin tray / vent, this should give you visibility of most of the flaps and you can then verify if they are working as expected.
If the blower motor is giving up after a while, the resisitor could be faulty. Not all models had it though, depending on the system installed. Eg. Climatronic, climatic etc
Mine has Climatronic (digital dual zone climate control) and doesn't have a resistor.
The resistor is a match box sized thing, located behind the glove box, with a green coating. It has a white plastic loom connector.
Apologies if I've repeated anything from those threads above.
Hope this helps.
Jason
