Have upright frost free freezer alarm is going off about once or twice a day.Put a thermometer it is around 20 degrees I mute the al;arm and it beeps again and again after several hours. looked to clean coils and can't find any coils under or in the back Can you help is it a thermostaste, fan, or bad sensor?

The light may be staying on and creating heat, or the unit thinks the door is still open.

Or the door seal is worn and is letting cold out.

Or

It needs gas.

Have you put a thermometer inside to check the temperature? It should be 0'F +/- 2'.

https://www.google.com/search?q=Kenmore+upright+freezer.+The+alarm+keeps+going+off

..

Control board is miscommunicating with the rest of your unit. Contact a professional.

I have had the same problem with my frigidaire/electrolux upright freezer... I am researching to see if there is a pattern. Once or twice a year for the past few years, the freezer defrosted itself. I found the outside of the unit to be VERY hot to the touch around the time that this occurred.
We typically unplug it for a chunk of time when this happens and then replug it. It has always begun working again.
Sadly, we have lost many groceries and have had to clean many bloody meat messes as a result of this. ANYONE buying this freezer should save their receipt... That way, they can return it or have it repaired when it fails. I hate to think of sending all of these failing monstrosities to the landfill... =(

i had the same problem and it turned out to be the sensor, a $15 part. it pretty much controls everything related to defrosting.

kenmore elite, alarm kept going on and b flashed on and off. I finaly figured out on bottom of freezer there is a battery door open it and change 9v. thats it,

Faulty alarm.

You need to check the temp in the freezer to make sure it's down to around 10 degrees. The alarm will go off much above that.

Hi: Does the freezer have a battery backup for the electronics? A 9v. battery in the grill down below. You won't have to remove the grill but pull a small rectangular panel to expose the battery. High end Kenmore freezers have a battery to back up the alarm. The six you see is actually supposed to be a "b" for battery most likely. L.E.D.'s are tough to tell the difference. Buy an new battery and all will be well. I hope this helps, Jeff

Your defrost timer, switch or circuit board is probably shot or it would be defrosting.

Use a fridge / freezer thermometer to tell if temperture high (it should be 0 F plus or minus 5 degrees) to determine if it is too high - this is normal if frost builds up but will get worse unless repaired.

You probably have a defective thermostat or sensor for reading the temperature.