Lenovo ThinkCentre M55 - Manual (Page 38)

4. The system fan assembly is made up of two pieces: an air baffle and the
system fan. Remove the air baffle by squeezing the two tabs 1 and pulling it
out of the chassis.
5. Remove the system fan by pressing the two tabs.
6. Insert the new system fan.
7. Reinstall the air baffle.
8. Reconnect the fan cable to the system board connector. See “Identifying parts
on the system board” on page 4.
9. Reinstall the front bezel.
10. Go to “Completing the installation” on page 34.
30 Hardware Replacement Guide