Here are your parts. Your model number was missing a couple digits at the end so I used a FRS20ZRGB2. The parts are likely the smae for most of this series.
Parts for Frigidaire FRS20ZRGB2 Refrigerator - AppliancePartsPros.comThe defrost timer (item 23 in the Controls Parts section) is at the front/bottom/left side. You may not be able to see the actual timer as often they are behind a mounting bracket. There is usually a hole in the bracket to allow you to turn the timer cam.
[COLOR="Blue"]now defrost fan is cycling where as before it never shut off.[/COLOR]
This in not really a defrost fan. It is an evaporator fan and it's function is to pull air through the evaporator coils to cool it. It also distributes this cold air throughout the unit.
During normal operation it should be on whenever the compressor is on, so it cycles once set point temperature is reached.
During defrost it is shut off so that the warm air from the defrost heater is not circulated into the freezer compartment.
[COLOR="Blue"]I am wondering why working now and if I should have concern with the defrost timer, I could not locate.[/COLOR]
When you had an iced up evaporator coil the fan could not pull air through the coil. So the air did not cool properly and therefore the freezer was not cold enough. The fan ran all the time because the compressor was on all the time trying to get the temperature down to set point.
Now that you have defrosted the unit it will run properly untill the evaporator coils ice over again, This could be a couple days or even up to a week.
[COLOR="Blue"]Where is defrost timer located and how can it be checked?[/COLOR]
Odds are very high the the timer is OF. You really cannot check it until after you replace the defrost heater.
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Also, how can I determine age of this unit, it came with house, I am guessing it to be around 8-10 years old.[/COLOR]
Not sure. below is info on how to read the unit's serial number.
Electrolux / Frigidaire / ICON
Serial Number breakdown:
1st Numeric Character = Last Digit of Year Manufactured
2nd and 3rd Numeric Characters = Week of Year Manufactured
Example, LA81503430 was manufactured in the 15th week (April) of 1998.