Abstract: The present invention comprises a control system for automatically controlling the height of a header on a combine. The combine header includes a cutter bar which is adapted to float upwardly and downwardly in response to variations in the terrain. A linkage interconnects the cutter bar with a movable cam and a microswitch so that the microswitch is actuated in response to upward and downward movement of the cutter bar. The microswitch is connected to solenoids within a hydraulic valve and the hydraulic valve is connected in the hydraulic system with the hydraulic cylinder for raising and lowering the header. When the cutter bar lifts upwardly the microswitches are moved to a condition wherein they cause the valve to actuate the hydraulic cylinder for lifting the header. Similarly when the cutter bar moves downwardly the hydraulic cylinder is actuated to lower the header. When the cutter bar is in a neutral position, the hydraulic cylinder remains motionless.