I have a Kenmore Frostless 19 Upright Freezer that up until today seemed to be running normally. My mother gave it to me about a year ago and she had no manual with it. It seems to be running all the time now. I tried turning the temp control down to 1 to get it to shut off and it will not. The only wat to shut it off is to turn the temp contol to off. Is there something else I could try?Model #253.9239711.Please help.