2005 Buick Terraza electrical problems

The rear power vent windows (both left and right) and the rear wiper motor have stopped working at the same time. What can I check for the problem? There does not seem to be a fuse or rrelay listed in either fuse panel/power distribution center for either of these devices. Is the a harness connector that controls both that could have come loose, or a power relay associated with borh?