Hello community
While cleaning, I accidentally removed the upper mounting bracket for the left inner fan.
It consists of two rubber clips that are held in place by a strip inside the housing.
Does anyone know how I can reattach these two brackets to the printer?
Does the strip need to be removed for this?
Do you mean you have removed the rubber screw from the cross beam? These rubber screws are installed through the back side of the beam, to put them back on, you have to remove the left side panel to re-install them. There should be a wiki to install the fan which shows the screw installation.
Edit: here Auxiliary Part Cooling Fan Replacement Guide for the H2 Series | Bambu Lab Wiki
Thank you so much, you’ve been a great help. 
