It depends. Your model is new enough that it may have a control board and thermistors in it. Then again, it may have (some or all) bimetal switch thermostats and a gear-driven defrost timer in it. Or it could have both.
Either way, if the defrost timer circuit has problems, the unit will never go into that mode. With both, you can force defrost mode to check that it works. The gear timers are usually near the evaporator, and some even have an access hole to stick an allen key or screwdriver, so you can test operation without taking anything apart. The electronic ones have a button or jumper on the control board that initiates defrost. They are easy to get to once you find the board.
Before you do too much, find a repair manual online and skim through it. These units also have a mini manual hidden inside the back cover somewhere, too. It will have a map that tells you where all the "secret" parts are and how to work them for testing.
From your observations so far, it doesn't sound like the unit has lost its charge. Home fridges don't contain enough charge to leak out slowly. If the thing develops anything resembling a leak, its cooling days end quickly.
|