Speed Control Will Not Turn Off With Off Switch

Turn ignition off. Unplug 10-pin connector from servo. While pressing OFF switch, measure resistance between servo harness connector pins for command switch signal and command switch return. See SERVO CONNECTOR PIN IDENTIFICATION  table for pin numbers and wire colors. Rotate steering wheel through full range while making measurement. If resistance is less than 4 ohms, temporarily substitute known good servo, then retest system. Go to next step. If resistance is less than 4 ohms, replace switch.