How to Connect Case Fans

Last Updated: August 10, 2021

Insufficient cooling is a common source of computer malfunction. Hard drives and system processors, or CPUs, are especially vulnerable to overheating due to insufficient cooling. Installing additional case fans is typically an effective method of providing additional cooling to the interior of a computer case.

This article provides step-by-step instructions for multiple methods of providing extra cooling to system components by installing additional case fans.

Method 1

Method 1 of 2:

Add a Case Fan to the Interior of the Computer Tower

1
Connect a case fan to an open space on the rear-inside panel of the computer case. Some computer towers will provide extra space on the rear panel of the case designed specifically to accommodate additional case fans. If the case fan to be installed will fit in the space provided on the vented, back panel of the case, it can be attached using 4 to 6 1/8 inch (4.76 mm) screws and a Phillips-head screwdriver.
- Attach the case fan to the vented, rear panel. Power down the computer and turn the power switch off on the power supply, which is typically situated on the back of the computer tower near the AC power cord. Position the fan over the vented area. Line the screw holes in the fan up with the venting holes on the back of the case. Using a screwdriver, insert at least 4 screws into the corresponding holes in each corner of the case fan.
- Connect the fan to the power supply. Locate any empty, 4-plug power connector coming from the power supply and plug the fan into the connector. Replace the side panel door on the computer case, and turn on the power switch. The additional fan has been connected.

Method 2

Method 2 of 2:

Attach an Additional Fan to the Side-Panel Door of the Computer Tower

1
Mark the case door for drilling. When there is no room left on the vented back panel of the computer case, a fan can be attached to the side-panel door of the tower. Mark and drill a series of holes near the rear of the side-panel door to attach and vent the supplemental case fan. Measure the distance between the screw holes located on each corner of the case fan. Use a marker, crayon or a grease pen to mark the location where the holes will need to be drilled on the side-panel door.
- Use a straight edge ruler to draw 2 straight lines running diagonally between the marks for the screw holes, forming an "X" on the side-panel door. Using a straight-edge ruler, draw a straight line vertically through the center of the "X," and another line horizontally through the "X."
2
Drill the holes for the case fan. Use a 3/16 inch (4.76 mm) drill bit to drill holes through the first set of marks made to match the screw holes in each corner of the case fan being installed. Now drill holes, evenly spaced, along each of the diagonal, vertical and horizontal lines. The venting and screw holes have been drilled.
3
Attach and connect the case fan. Hold the new case fan against the inside of the side-panel door so that it lines up with each of the 4 screw holes. Insert a screw through each corner of the case fan. Locate an available 4-plug power connector coming from the power supply, plug the fan in and replace the side-panel door. The supplemental case fan has been installed.