Case fan. Photo used under CC-BY-SA license from William Hook.

The following steps will enable you to install a case fan. First, you must ensure that your PC is powered off before you install any component in your system. After opening the case, you will need a Phillips head screwdriver in order to remove/install case fans. If you’re replacing a fan, simply remove the old one by unscrewing it from the case and unplugging the cable from the header (or the MOLEX connection, if you have an older system). To mount the new fan, hold the fan up to the mounting position so that the holes for screws line up with the holes in the case. While holding the fan in place with one hand, with your other hand use four screws to secure it in place. Some models use plastic friction clips to hold the fan in place instead of screws. If the system is like this, simply un-snap the clips, remove the fan, and pop the new one in its place.

After you secure the fan, you need to attach the fan to an unused fan header to provide the fan with power. The headers are keyed to ensure a proper connection and prevent you from plugging them in backwards. Four-pin headers will work with three-pin fans, but you will not be able to control fan speeds, since this is only performed by the fourth pin in the connector.

When you are done installing the fan, make sure you route your fan and other cables using proper cable management techniques and some zip-ties. Proper cable management prevents the fans from hitting the cables when they spin and also aids in proper airflow to increase cooling efficiency. Be sure to power up the computer and make sure the fan is working properly.

Red case fan. Photo used under CC-BY license from Airplane Lane.

In the lab exercise below, you should remove the old case fan and install a new case fan. Be sure to use proper safety precautions. For the purposes of this lab exercise, you can assume that ESD precautions are in place.