2004 LeSabre temperature gauge does not return to zero

PROBLEM:  TEMPERATURE GUAGE DOES NOT GO BACK TO ZERO
WHEN IGNITION IS TURNED OFF.  AFTER A COUPLE OF OPERATIONAL
SEQUENCES TEMPERATURE GUAGE WILL RED LINE AND NOT
RETURN TO ZERO.  IN ORDER TO GET THE TEMPERATURE GUAGE
BACK TO ZERO, CAR NEEDS TO COOL OFF.  THEN I NEED TO CYCLE
THE KEY WITH OUT STARTING IT SEVERAL TIMES, MAYBE (10), TO
BRING THE GUAGE NEEDLE BACK DOWN TO ZERO.  NOTE:  ALL
OTHER GUAGES WORK PROPERLY, AND ALL LIGHTS OK.
SOLUTIONS TRIED:  REPLACED THERMOSTAT, REPLACED
TEMPERATURE SENSOR, AND REPLACED RADIATOR CAP.  NO LEAKS,
COOLANT IS FULL, CAR IS NOT OVERHEATING.
QUESTION:  DOES THIS SOUND LIKE A BAD STEPPER MOTOR   A
COMPUTER OR PROGRAMING  PROBLEM?