Please Help..Freezer is at 24-34 degrees

Bottom freezer fridge by Samsung model RB215LASH
The top fridge part seems to stay at a constant 36 degrees all day.
The bottom freezer stays around 24 to 34 degrees.
I checked the condenser fan and it seems to be running cycling on and off all the day, so I assume it’s working.

Do you think it maybe the start relay?

Also the fridge (top part) makes a rumbling sound on the back which is intermittent.

Thanks for your help.
-Al

Here are your parts
Parts for Samsung RB215LASH Refrigerator - AppliancePartsPros.com

Here is a service manual. Your unit may not be an exact match but it should be close.
http://appliancejunk.com/forums/index.php?action=downloads;sa=downfile&id=395;t=1437558319
You will have to join the site and be logged in.

I doubt the problem is related to the compressor as it is cooling.

Remove the covers in the freezer and check the evaporator coils.
If they are heavily iced/frosted over it could be a defrost problem.

Also try running the diagnostics to see if a fault comes up.

Thanks denman.
I did check and the bottom freezer back wall is frosted.
I did the self diagnostics as you suggested and it shows:
R- Defrost error
and
C-Fan Error.

Which parts do do you think need to be replaced?
thanks, much appreciated.

The C-fan is probably the condenser/compressor fan so check that it is running OK.

I am not sure what R-Defrost error means.
I think the R is the refrigerator side (fresh food).
I would remove the cover and check that the evaporator coils are not iced/frosted over heavily.