Defrost button on semi automatic refrigerator

[jimjoe12345]

A newbie here, just joined.

This topic probably belongs in 'Appliance Repair Tech Forum" but there I didn't see "Start new topic" option, so I am posting my question here hoping admin can post it to the appropriate section.

I live in Philippines where "semi automatic defrost" refrigerators are still used.  I have LG 7cuft, GN-B331SLZ which have a blue button(defrost button) inside temperature control turn knob.  See attached photo file.

BTW I am asking the question here cus just curious "how things work".

Intend for blue button(when pressed a "click" sound) is to start defrost then later blue button "pops out" to stop defrost and back to normal operation.

Curious thing happened.  Entire refrigerator was FROZEN.  YES, even in refrigerator section (not freezer section), on all shelves, containers were FROZEN like freezer section.

 So I check several things, including turning temperature to LOW(warmer) setting, and still freezing.

Then by chance, I pressed blue button and found out that it was already "depressed", no "click" sound anymore.  Now this would mean that refrigerator have been in "DEFROST" state all along, then it should not freeze, instead should have water all over refrigerator(like after defrosting).   BUT "depressed" blue button was causing everything to FREEZE.  just opposite of what I expected to happen.

So the question is "what happened"?  What caused FREEZING? How does thermostat work? Blue button work?  What happens to thermostat when blue button is pressed?

Can somebody explain how "semi automatic" defrosting thermostat work? What happens to thermostat when "blue" button is pressed?

Thanks in advance,