[skibumynn]

Refrigerator and freezer not cooling adequately. I hear a clicking every 2-3 minutes that sounds like the compressor coming on. It stays on for about 15 seconds, then shuts off again until the cycle repeats 2-3 minutes later. Refrigerator temp is about 45°F, with freezer slightly colder at lowest setting. Fan/relay/control board?????

[PNWDrew]

The noise you hear is the compressore trying to start as you say. I'd say one of 2 things is happening.
#1 - The Adaptive Defrost Control board is failing to bring it out of defrost successfully. The ADC is responsible for shutting the compressor off and turning the defrost heater on and vice versa.

or

#2 - The start device or capacitor on the compressor is weak.

I'd expect it's the ADC before the start device. You may unplug it for 10 minutes or so and see if that resets the ADC, that isn't a solution but it helps diagnose. Sometimes you can access the ADC and lightly tap the relays with the nonconductive handle of a screw driver and get it to advance back into run state. That is also not a positive test however, just a quick way to diagnose if you are lucky.

There are a few more unlikely scenarios that would require some electrical testing to check. If you have a multimeter, you could check and see if the power to the compressor is actually being cut off by the ADC repeatedly.

Have fun with it...