Dell NOT21684 Owner's Manual page 69

Prerequisites
If you are replacing a component, remove the existing component before performing the installation process.
About this task
The following image(s) indicate the location of the fan and provides a visual representation of the installation procedure.
Steps
1. Align the screw holes on the fan with the screw holes on the palm-rest assembly.
2. Replace the two screws (M2x4) that secure the fan to the palm-rest assembly.
3. Route the fan cable through the routing guides on the palm-rest assembly.
4. Connect the fan cable to the system board.
Next steps
1. Install the base cover.
2. Install the SIM card.
3. Follow the procedure in
68 Removing and installing Customer Replaceable Units (CRUs)
After working inside your computer.