Remove the Cooling Fan for Hotend
Step 1: Loosen the Part Cooling Fan
Unscrew the 3 screws of the part cooling fan. Note that the screw at the back is shared with the toolhead rear cover.
After loosening the screws, the fan will naturally hang down.

Step 2: Loosen the Toolhead Rear Cover
Remove the 2 screws on the top of the toolhead rear cover to open the module interface cover;
After opening the cover, gently push the toolhead rear cover from the inner wall with your fingers to release it.

Step 3: Disconnect Connectors on the TH Board
Disconnect the hotend heating assembly connector.
Peel off the acetate tape covering the hotend fan connector.

Step 4: Remove the Hotend
Refer to this tutorial for hotend removal: Replace the H2S Hotend https://wiki.bambulab.com/en/h2s/maintenance/replace-silicone-sock-and-hotend
Unscrew the 2 screws securing the cooling fan for hotend and remove it.

Install the Cooling Fan for Hotend
Step 1: Install the Cooling Fan for Hotend
Route the cable of the new cooling fan for hotend into the cable channel.
Align the fan with the label side facing the hotend, matching the screw holes (refer to the red and yellow circles in the image below).
Fold the fan cable into the designated groove before securing the fan.
Tighten the two screws to secure the fan.

Step 2: Install the hotend
Refer to this tutorial for hotend installation: Replace the H2S Hotend

Step 3: Connect the plug to the TH board
Place the plug's jack facing the socket on the TH board, align it, press down the plug, and connect the fan cable;
Re-attach the acetate tape;
Pre-align the screw holes of the fan, arrange the fan cable on the TH board, and pull it upwards, fold the cable to prevent it from being crushed by the fan housing or the toolhead rear housing of the toolhead and causing fan abnormality.
After arranging the cables, insert the hotend heating assembly plug, and use the hotend heating assembly plug and cable to press the part cooling fan cable.

Step 4: Install the toolhead rear housing
Install the toolhead rear housing;
After installation, make sure the part cooling fan cable is in the dedicated notch to avoid being squeezed by the rear housing frame.
Tighten the 2 rear cover fixing screws.

Step 5: Install the part cooling fan
Align the screw holes and install the part cooling fan; when inserting the fan, be careful not to press the fan cable.
Tighten the three screws to secure the cooling fan.

Verify the Functionality
Power on the printer and set the hotend temperature to 100°C. After a few seconds, the cooling fan for hotend should start to spin, and the installation is complete.