Step 3 - If you have rear air you have to do this. I tried not to and broke the outer cover for the heater core. So If you have rear air you have to pull the carpet back. To do this you have to take out the seats. Unbolt the seats by removing the bolts that hold down the rear of the seats. Then pull the seats back to free them from the front hook/latch. Once the seats are free disconnect the battery. Then unhook the electric from the bottom of the seats. Then the seats can be placed outside the car. Then pull the carpet back. You will have to remove the trim pieces the cover the sides of the carpet. You need to get the carpet over the shifter in order to remove the ducting. Once the carpet is back you can just lift out the ducting.
