Here are your parts
Parts for ARSE667BC - AppliancePartsPros.com

See the attachment for the tech sheet

Also below is a manual that you may find useful.
You will have to join the site and be logged in to be able to download it.
http://appliancejunk.com...&id=382;t=1411638244

First remove the evaporator cover in the freezer so you can see the coils.
If they are heavily iced/frosted over then it is a defrost problem.
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 defrost.

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 ADC board needs replacing, re: it is never getting into a defrost cycle.

If not on.
Unplug the unit.
Remove the wire for one side of the heating element from the wiring and measure it for continuity, usually around 30 ohms or so.

If the heater is OK
Remove one wire to the defrost thermostat 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 board is toast.