A horizontal ejection system for a vehicle. An ejector is adapted to travel axially through the interior from the front to the back of the truck body. A hydraulic system includes a hydraulic circuit for moving the ejector, and an ejector signal processing system signals the hydraulic circuit. The ejector signal processing system includes one or more proximity switches for detecting the location of the ejector and triggering the movement of the ejector. The switches are disposed on the truck body to sense the location of both the ejector and the tailgate. As a result, the hydraulic circuit is signaled to control the hydraulic system and thereby move the ejector based on a position of the ejector and the tailgate, wherein, in combination, the ejector and the tailgate control a load of material within the truck body.