If the blower is working and the air won't come through the defroster, there is a problem with the blend door. It is a plastic door which directs the air flow in different directions. What will need done is the face plate will need removed from around the heater control. That doesn't sound like much to do, but the air bag becomes an issue. Any time the air bag is an issue, I recommend that the owner take the vehicle to a certified mechanic.
If you still want to do it yourself, I recommend that you purchase a manual for your car. It will list step by step instructions and provide pictures for part identification.
I hope this helps you.
Friday, October 31st, 2008 AT 1:33 PM