Sel Z,
Inputs should pass through the fuse and on to the input of the crossover. Hopefully, the xlr is parallel. It would be odd that someone added the xlr as given a choice to modify an input that is the last thing i would do. As suggested, they could have been used with a subwoofer but I don't know that any subwoofers come with the xlr connector. Maybe someone had some KP-450 bottom cabinets and added the xlr to mate them with the 201s. Bottom line, you need to pull the input panels and take a look.