G.E. electronic side x side still not defrosting after board, heater & bi-metal

[davidbriggs]

I have been fixing appliances for a living now for over 20 years but have been stumpted on a couple of G.E. SxS refs. with defrost issues.  It is normally a burnt out heater which would be clear with the ohm meter.  The defrost thermostat or hi limit bi metal is usually clear but can be intermittent and happen to be in a closed position when you check it.  I had one with a loose plug in the freezer wall harness connection.  I now do a live current check with a jumper wire at control board to the heater to check for possible wiring issues.  Both of the 2 stumping me have had a new heater, bi metal and control board.  The first one had two new boards and I am able to power up the heaters by sending power from the control manually with jumper.  I am assuming that the problem now is with a thermistor.  I checked the door switch (have had issues with fresh food door adjustment screw moving and dropping door away from top switch models).  There is nothing left but the thermistors, right?!  

[BrntToast]

ge changed up the boards a while back, some models require rewiring of the harness, maybe you have one of these

i believe the wiring change has something to do with the thermistor

one of the other techs with more GE expierience should be able to shed more light on this one

i had one friggy stump me for a bit, turned out it was running the compressor during defrost

[davidbriggs]

On the first of these two refrigerators, I double checked the instructions that came with the board but still ended up with a frost up again.  On the second,  another company had been there already and replaced the board.  Had the customer not have told me that, I would have been changing the board again.  Assuming intermittent failure somewhere else, I changed the bi metal and checked the harness plug.  I did a live check of heater and replaced it anyway as they fail often. 

[Mr. Fix-It]

The thermistor is usually the first thing I change on these as they are cheap and cause these problems 9 times out of 10.