I bet it is your thermostat that is bad. They do things like that sometimes when they go bad. They either stick in the off position or the on position. The part number is #2198202
Whirlpool WP2198202 Cold Control - AppliancePartsPros.com
I think the model number on your fridge is wrong. I believe the X and the M are reversed. Anyway most of these refrigerators took the same thermostat. This place is about $20 cheaper than $ears.