A vehicular slider window assembly includes a frame having upper and lower rails. A fixed window has an opening and the rails are attached at the fixed window. A movable window is movable between a closed position and an opened position. A carrier disposed at a lower edge of the movable window moves with the movable window between the opened and closed positions. A sensing system determines when the movable window is in the closed position and includes a switch assembly that is actuated when the movable window is in the closed position. The switch assembly includes a switch device within a housing. A portion of the housing is an end stop configured to limit movement of the carrier when the movable window is in the closed position. The switch device includes a contact and, when the movable window is in the closed position, the contact actuates the switch device.