If none of the contacts of a manual switch change status when activated, what is the most likely cause?

When a manual switch is activated and none of the contacts change status, it typically indicates a mechanical issue with the operator. This situation suggests that while the switch is receiving the input to change position, there is a failure in the mechanism that translates that input into a physical change in the contact positions. This can happen due to wear and tear, a misalignment, or a physical blockage that prevents the switch's internal components from making the necessary connections.

Considering the other potential causes, an electrical short usually results in unexpected behavior, such as contacts remaining closed when they shouldn’t be, rather than a complete lack of change. Incorrect wiring might lead to improper contact behavior, but it wouldn't typically cause the contacts to remain unchanged upon activation of the switch itself. A problem with defective contacts might lead to a failure to make a reliable connection when engaged, but would not inherently stop any change from occurring. Thus, a mechanical problem with the operator of the switch is the most plausible cause for the lack of status change in the contacts when activated.