I have an electrical enclosure that I'm trying to punch holes into for a new assembly. To start, I downloaded the attached files from the supplier website. I opened one in Solidworks, saved it as a SLDASM, and tried to make an extruded cut on a side wall. The extrude and sketch are clearly shown on the feature tree, but the extrude is not visible on the 3D model.

It might be because the enclosure is made of surfaces. I tried to knit or thicken, but both operations fail. I'm not sure what else to try. Any ideas?