I supposed my first question would be...other than the harness, does the section update as expected? If you've added a bolt, is it shown? Could be tested if your not sure.
Is the harness created using surface models or solids or just the thick centerline shown?
Check layers in the drawing to make sure something wasn't turned off unexpectedly. (unhide them all temporarily to check, regen the sheets, verify) After you are finished testing, go back to "reset status" on the layers to get them back like the were or if it solves the problem, save status or figure out which specific layer is the culprit.
If its solid, well, maybe just make sure the section is correctly positioned so the harness would be seen, I can't think of anything other the layers for solids.
For surface, well, usually the surfaces show thru everything, instead of not showing at all. So, it's more back to layers.
I'm not completely sure how the centerline version shows on drawings.
Maybe there is a tidbit of something helpful in my ramblings
