[mozeyko9]

Our Samsung refrigerator is 2.5 years old. It is a side by side refrigerator/freezer. The freezer section is working fine. The refrigerator will not cool properly. The refrigerator temperature will fluctuate from 34 degrees to as high as 64 degrees before it begins to cool again. Periodically, we will find water at the bottom of the refrigerator. When it does cool, it only lasts for a short time. I am assuming that there is a problem with the defrost cycle but would appreciate any advice about next steps in isolating the problem and then attempting the repair. Thanks

[woodchuck]

If the evaporator coils behind the back panel of the freezer are icing up because of auto defrost failure that will stop the circulation of cold air and eventually affect the freezer too. Your heater may not be melting all the ice letting it ice up again so quickly.
Remove the back cover in the freezer to observe the frost pattern. stopped up? clear? ice in one spot . frost everywhere.

check defrost timer, defrost heater, defrost thermostat---Refrigerator Repair Guide: How To Fix a Refrigerator - ACME HOW TO.com

In most of the new units they now have the adaptive defrost control instead of defrost timer.. It senses when to defrost based on how many times and for how long the door is opened. It's more energy efficient but there does seem to be lots of problems with the board.

[mozeyko9]

I removed the back cover in the refrigerator. There was ice and frost everywhere. I manually defrosted the coils. The refrigerator is cooling again. However, i expect that the fix is temporary until the ice and frost builds up again. I viewed some other threads concerning a Samsung refrigerator with the same problem. The fix appeared to be replacing the PBA control board. Do you know where this part is located?

[woodchuck]

Looks like part 26 in this diagram and parts list. Maytag Appliance rs267labp Parts List

Make sure your heater works before spending 200.00 for that part.