What you need:
- Car A/C Vent
- 80mm 12V PC fan
- Bunch of styrofoam (from laptop and gadget boxes)
- Double-sided foam tape
- 12V power supply or battery
I found a slightly damaged BMW E46 A/C vent that was about to be disposed. I saved the item and gathered my 80mm 12V PC fans. Unfortunately the fan is too big for the vent, and I would need to make a path for the fan so that it doesn't leak. In this instructable I will use styrofoam to stuff the vent surroundings and thus allow the fan wind to travel only into the vent itself.
Begin cutting the styrofoam into desired piece of boxes that will enclose the vent. Use double-sided foam tape to securely attach the styrofoam around the A/C vent body. Finally, attach the double-sided tape into the fan's sidewall to secure it into the styrofoam housing.