Abstract: A motor-driven window regulator for use with a horizontally sliding window installed in the rear window opening of a pickup truck cab. The sliding window is moved between a closed position wherein it fills a gap between two fixed, outboard mounted windows and an open position wherein it slides to overlap one of the fixed leaving the gap open. The sliding window is actuated by a pair of linear actuation cables, each of which is attached to the sliding window at a first end and to a motor-driven cable drive drum at a second end. The linear actuation cables extend away from the sliding window in opposite directions parallel with the direction of sliding movement and wrap around the cable drive drum in opposite directions so that rotation of the cable drive drum in one direction places a first cable in tension to pull the sliding window toward the open position and rotation of the cable drive drum in the opposite direction tensions the second cable to pull the sliding window toward the closed position.