Kenmore 795.78.402 refrigerator. Is the fridge main board bad?

The fridge gets its cold air from the freezer through a vent(damper) between the freezer and fridge.The fan in the freezer blows air through it. Make sure this fan is running. You may have to hold the door switch in for it to run. There is a flap you adjust with the fridge temp. control. Make sure it's opening and closing when you adjust the fridge temp.
The problem could be the electronic control if you have one or the mechanical linkages.

The compressor relay is bad on the main control board . Unplug the refrig and pull the refrig out and remove the 8X10 small panel on the back . You will see a blue plug with 3 larger (120v) wires going to it . Remove this plug . Looking at the plug , you will see : wire1 , wire2 , space , wire3 . (this is on the plug NOT the board ) . Using a short piece of insulated wire , with about 1/4" stripped off both ends , insert 1 end into wire1 and the other into wire3 . Plug the refrig back in . This will start the compressor to verify the main control board is bad . Pt # WR55X10942 .

Excuse me , but your fan works off 6-9 volts DC so do not try 120 volt cord . Your refrig has no defrost timer . It works off thermistors and a main control board .

Pull the refrig out and remove the 8 " x 10 " panel . Behind this panel , is the main control board . Unplug the refrig . Remove the BLUE plug from the board , with 3 larger wires going to it . Looking at the blue plug , the sequence will be wire1,wire2,space,wire3 . Get a short piece of insulated wire , and strip about 1/4 inch from each end . Insert 1 end into wire2 , and the other into wire3 . Plug the refrig back in . After about 3 min , look in the freezer , at the bottom , behind the crisper , look for a red glow . If no red glow , unplug the refrig , and reassemble the plug and cover . This no glow , indicates a shorted defrost heater WR51X10055 . It is also advisable to replace the defrost thermostat ( pt. number WR50X10068 ) when replacing the heater . To access these parts , you will have to remove the inside rear wall of the freezer . The heater , is at the bottom of the coils , held on with 2 screws , and the thermostat , is the 1 " cylinder , with a blue and pink wire going to it , clipped on the top left of the coils .
If you do get a red glow , then the # 4 thermistor is bad . This tells the main control board , the temp of the coils , if they need defrosted , when they are thru defrosting . This thermistor is the 1 " long , torpedo looking piece , clipped on the top left of the coils , with 2 white wires going to it . Part number WR55X10025 . It would be advisable to also replace the # 5 thermistor , located at the bottom of the freezer , slightly in front of the drain , also with 2 white wires going to it , slid into a housing . This thermistor , is the freezer thermistor , which tells the control board , the freezer temp and when to cycle off at selected temp.

Hi:
This prolem could be one of two problems, first the inverter board may have bad connections on it, its used to light the lamps in the back of the PDP Panel (SCREEN) second the Digital board may becoming faulty, there may be a faulty IC on the digital board or main system control board.
But first I suggest you take off the back and disconnect all plugs you see and reinsert then firmly to make sure they are on tight.

Hi,
With fridge freezers, there is usually a solenoid at the back that controls where the refrigerent goes. It consists of a sealed valve and a solenoid coil. It is possible that this has become open circuit so cannot direct refrigerant to the freezer section.
Another alternative problem may be the thermistor in the freezer section. This sensor will tell the control board the temperature in the freezer section. If it gets it wrong, then the freezer will overcool or not cool at all. Often a manufaturer will standardise on a part, so swapping the fridge and freezer thermistors around can identify that this is the fault - then just buy another 1.
If these tests don't work, you're looking at a new control board. Second hand ones may be available.
Best of luck.

Mark Remove the rear panel in freezer. Apply 3n1 oil to fan motor shaft and plug in and spin. I believe they left the freezer shut and the moisture froze the shaft on fan with rust. Once restarted you will be fine. Sea Breeze

Is the freezer fan working ? If not , control board probably bad . Pull refrig out from wall and remove power . Remove the 8" X 10" panel and you will see the main control board . Remove the blue plug with 3 larger wires . The sequence is : wire1 , wire2 , space , wire3 . Using a short piece of wire with both ends stripped about 1/4 " , insert the wire into wire2 and wire3 . Plug refrig back in . Look in the freezer at the bottom rear for a red glow ( may take a minute or so ) . If you see a red glow , the main control board is bad ( the board you unplugged the wires from ) . If no red glow , then disconnect power to fridge , remove the jumper , and reinstall the blue plug and the panel .
Remove the food from the freezer section and remove the rear freezer panel inside the freezer . There you will see a round 1 " disk , clipped on top of the coils .Pt # WR60X10068 Defrost thermostat . At the bottom of the coils , you will see a heater . Pt # WR51X10042 Defrost heater . Replace both of these as the heater gets hot , and cuts off by the bimetal . he heater only has a screw on each side attaching it to the coils , and the bimetal just clips on . Easily repairable .

Is the fan in the freezer working ? May have to press the light switch in to test . If not , main control board is probably bad . not the fan moter . Pull refrigerator out and remove the small 10"X13" metal cover . Unplug refrig first . Then remove the blue plug with 3 wires attached to it . The wire sequence on the plug looks like this : wire 1,wire 2,space wire 3.
Use an insulated jumper wire with both ends stripped and insert one end into wire 2 and the other into wire 3 . Plug refrig back in and look in freezer at the bottom . If the heater and defrost thermostat are good , the a red glow should appear . No red glow , either bimetal or heater is bad . Most likely heater pt# WR51X10101 . Do not forget to reinstall the blue plug with refrig unplugged or could cause main board dammage .

yes that does sound like a bad evap fan motor then unable to circulate air aorund and off hte evap thus building up frost.you can pull the wire leads of the fan motor and ck for 110v. to confirm that you are indeed getting power to the motor.

Great advice from medeer, I had the same ER DH error code, and my refrigerator began to warm up. I replaced the defrost thermostat assembly part # 6615JB2005H which is located inside the freezer, on the right side behind the white plastic panel. I accessed it by removing the freezer door, all components inside the freezer, and the tracks mounted on the sides of the freezer. Be careful when removing the white panel because a fan is mounted to the left side of the white panel and plugs into the back left side of the freezer compartment.
Found the green technical data sheets under the refrigerator in a small plastic bag near the front.
My refrigerator is 20 months old, just a few months past the warrentee,