Just to share my 22+years Goldstar (it has renamed to LG) fridge that had served me well with 2 DIY repaired.
1st issue on last year, the "freezer and fridge not cold" although the bulb in it still light up. Done some research and testing, concluded the
Defrost Timer was faulty, bought the spare parts from ebay, replaced and it works like a charm.
A few month back, another new issue, this time, the "freezer was cold but not the fridge". I tried switch-off the fridge's power for few hours to totally defrosted and the fridge works well for about 2 weeks before same issue happened again. After several tests with the multimeter, found the
Defrost Sensor was faulty, bought the spare parts and solved the issue.
Some photos below...
1. The freezer was cold but it didn't defrost, so the thick ice blocked the cold air to cool the fridge's lower compartment --
https://imgur.com/a/dsQse
2. Defrost Sensor --
https://imgur.com/a/hBPAG
https://imgur.com/a/OILew
3. Continuity circuit test of the New Defrost Sensor --
https://imgur.com/a/ucQ0F
General reminder: Do not attempt DIY unless one have some basic electrical knowledge.