Dell OptiPlex 7020 (Mid 2014) - Manual (Page 21)

4. Pry and remove the system fan away from the four grommets securing it to the back of the
computer.
Installing the System Fan
1. Place the system fan in the chassis.
2. Pass the four grommets through the chassis and slide outward along the groove to secure in place.
3. Connect the system-fan cable to the system board.
4. Install the cover.
5. Follow the procedures in After Working Inside Your Computer.
Removing the Thermal Sensor
1. Follow the procedures in Before Working Inside Your Computer.
2. Remove the cover.
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