[chuck928]

My freezer coils ice up. this has not been a problem until now. the refrig
is not cooling enough. should i replace the defrost sensor?

[denman]

Here are your parts
Replacement parts for Kenmore 10656532400 | AppliancePartsPros.com

See the attachment for the tech sheet.
I am not sure this is the correct one. Yours may be behind the kick plate or taped to the inside or outside of the back cover.

First remove the evaporator cover in the freezer so you can see the coils.
Do not let them de-ice.

If yes.
Manually force a defrost cycle see the tech sheet. When the fans and compressor turn off, you are in a defrost cycle.

Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the board needs replacing, re: it is probably never starting a defrost cycle.

If not on.
Unplug the unit.
Remove the wire for one side of the heating element (AP4321914) from the wiring and measure it for continuity, usually around 20 ohms or so.

If the heater is OK
Remove one wire to the defrost thermostat (AP4299920) and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.

If both the above are OK then odds are the defrost timer contacts are toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo.

If you click on a parts picture often a new page will open wuth more info on that part.