YOU DIDN'T STATE THE BRAND/MODEL/AGE. BUT... I WOULD HAVE A QUALIFIED PERSON CHECK THE BASIC WIRING THROUGH THE CONTROL SWITCH AS WELL AS THE LIMIT SWITCHES. A LIMIT SWICTH MAY BE STUCK IN THE CLOSED POSITION OR THE UP/DOWN SELECTOR SWICTH MAY BE FAULTY. A SIMPLE VOLTMETER/CONTINUITY METER WOULD TELL THE STORY. GOOD LUCK
TERRY, May 2009