Kenmore Side by Side Frost Buildup

Refrigerator & Freezer Repair
1

I’m hoping someone can assist with my troubleshooting of Ice build up on a Kenmore Side by side (model# 79551312014). I have exposed the back of panel of the fridge several times and defrosted it. It is currently heavily frosted. Reading many of the posts on troubleshooting defrost problems in the forums, I am at a loss when looking for similar components in my refrigerator. The label says MFG DATE: 2013.06. I can only guess this means June of 2013, so it really isn’t too old, and I suspect some of the newer parts are different. I can seem to narrow it down to the:
1.) Refrigerator Control board-#6615JB2002R
2.) Refrigerator Defrost Heater - #MEE61843904
or 3.) Refrigerator Temperature Sensor - #6500JK1004A
[part #'s according to Sears parts direct, so likely over priced]

I have a multimeter, but all wires seem to junction at a single plug in the back upper part of the freezer. Any help in troubleshooting the correct part would be much appreciated.

3

It sounds like the defrost thermostat is bad, causing the evap coils to become iced over, rather than an even frost pattern.
You may have to cut the wires to remove the thermostat, then check for continuity both before, then while submerging it in a glass of ice water.
There should be a change when it is in the ice water.
Also, see if you can put it into a manual defrost while the back panel is off, to see if it defrosts.
The evaporator fan has to be running in the freezer compartment to circulate the air and prevent over frosting the coils. It will be on any time the compressor is running.