Hi: I have a dilemma I would greatly appreciate some advice on.For some time now I have noticed some weird noises from my side by side.(It still is cooling OK …so far).There is a lot of repeated clicking behind the temperature controls in the fridge comartment.According to my manual underneath it is the "defrost control".As it clicks(loudly) it is attempting to start the evaporator fan located by the sound in the freezer compartment.When it finally does start it seems to run smooth enough but I notice the evaporator fan is probably off more than it is on.I think the compressor is running OK as I don’t hear those too familiar sad relay clicks trying to start it and again it so far is still cooling great.I suspect problems in the defrost control,am I on track and have I given enough information?? Best Regards
Here’s a replacement adaptive defrost control board. It’s located in the control console shroud, behind the console itself. Make sure the wire harness is securely attached, and that there are no loose wires.http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5158563&diagram_id=1272383#d1272383
AP4909015
Thanks Magician59: Do you think that this part could be causing the annoying problem I described.It clicks like a relay is having trouble closing and "bumps" the fan as it clicks.Then after 8-10 loud clicks the fan starts and runs smoothly though it will stop after a while.I’m told most fridges cycle defrost about 20 minutes every 6 or 8 hours and only during the defrost cycle will the evaporator fan not be running. Your adivice is really appreciated.
I dunno: Most of the time, clicking noises correspond with relays (or poor wiring connections). I would also check the start relay on your compressor. The fans come on with the the compressor.
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5158563&diagram_id=891198#d891198
[part]AP4367355[/part]
I found underneath the shroud a control module and further toward the back some sort of damper motor that opens a vent between the freezer and the fridge for some reason.It is here that the repeated loud clicking noises come from.While the control module does not directly feed the damper motor it does input each on a separate wire back to the control module to indicate damper open or damper closed.When this damper is in one or the other position(can’'t see to tell) it appears to inhibit the evaporator fan.Any air movement in the fresh food section could only come when damper is open.I remain suspicious of either the control module or the damper but have no idea why there would be a vent between the two compartments.
The freezer is the part of your unit that provides the cooling. The damper controls how much of the cold air comes into the fresh food section. If wide open, and left that way, the whole unit is a freezer. The fan in the freezer circulates the air between the two sections.
Then the damper must be operated by the fresh food thermostat.The fresh food is cold yet not frozen so that must be working.The damper operator was doing the chattering.I worked it manually and haven’t heard the chatter since.
Does the evaporator fan turn off when this thermostat has closed the damper door or only when it is in defrost cycle?There is a feedback to the defrost module to indicate the status of the damper door.When the nuisance clicking of the damper mechanism stopped the fan started and stayed running.You know after all these years up until now I have never had to ponder the operating characteristics of a fridge/freezer. 
The evaporator fan and the condenser fan run when the compressor runs. In some models, the evaporator fan stops when the freezer door is opened, and resumes when the door is closed.
Thanks a lot Magician59.I really appreciate your help.