How to Install Computer Fan

Learning how to install a computer fan can be necessary when you build your own computer or when a fan breaks and needs to be replaced in an existing computer.  You may even want to install additional fans. You will need a screwdriver and 4 screws. The screws should come with a new  fan when you buy it or use the old ones. Follow these steps to install a computer case fan:

  1. If you need to buy the fan, check for the size on the old fan if you have it. If not, measure the space diagonally. This means from the corners that are furthest from each other.  This is how computer fan sizes are measured. You will probably need the size in millimeters.  A great place to buy computer fans is newegg.com. It should be easy to find the size you need there. 
  2. Turn off the computer and remove the power cable from the back of the computer. Remove the computer cover using screws on the back edge of the case or a tab depending on how the computer is designed.  
  3. Once you have the fan, remove the old fan if necessary by removing the screws on the 4 corners of the fan.  
  4. Plug the new fan's power connector onto either the motherboard or the corresponding cable coming from the power supply.  
  5. If you need to find what direction the fan moves air, plug it in and then start the computer for a short period and note the direction. If it is to go on the front of the computer, then have it move air into the computer. If it is to go on the back, have it move air out.  If it is to go on the side, you will probably want it to move air into the case.  
  6. Install the fan using four screws to secure the fan to the case.  
  7. Replace the computer power cable and test the fan. After you make sure it works, replace the computer cover.  

Source:

Celnet.org