[compsmart]

OK - so the freezer has stopped automatically defrosting - causing the refrigerator to warm up significantly. When this happens - I manually defrost the coil in the freezer with my heat gun and she's good to go for another week or so.

Can anyone tell me how best to troubleshoot exactly what part(s) I need to replace? Thanks!

[richappy]

When the compressor is running, unplug fridg. and take the motherboard cover off the back. Remove the 3 pin power connector and install in the connector a wire between the mating pins on the motherboard labeled line and def.
Plug in fridg, if it now defrosts, you have a bad motherboard AP4436216, if no defrost, replace the defrost heater and defrost thermostat.

[compsmart]

Originally Posted by richappy

When the compressor is running, unplug fridg. and take the motherboard cover off the back. Remove the 3 pin power connector and install in the connector a wire between the mating pins on the motherboard labeled line and def.
Plug in fridg, if it now defrosts, you have a bad motherboard AP4436216, if no defrost, replace the defrost heater and defrost thermostat.

Thanks so much for the troubleshooting advice Rich! Let me ask you - so when I jump the LINE and DEF pins - I'm then going to simply check to see if the defrost is working by checking that the defrost heater under the coil gets warm to the touch - correct?

[richappy]

That is correct, assumes the freezer is at freezing temperature and the compressor was running when you unplug it. Defrost action implies the motherboard is bad, locked up in compressor run mode.

[compsmart]

Just to update everyone:

I replaced the defrost element and defrost thermostat - a pretty straight forward replacement of parts - not really much to screw up. This didn't solve the issue.

I replaced the main board - and disregarded the instructions about clipping certain wires because even though the instructions said they were applicable to "all bottom freezers" - the colors and locations of the wires in the instructions did NOT seem applicable to my unit. This didn't solve the issue either!

I'm starting to get a little frustrated at this point as this thing is really kicking my but! LOL Is there anything else I should try before sending it to the appliance graveyard?

[richappy]

Remove both freezer and evaporator thermistors and check resistance, should be 16.3 k ohm after 5 minutes in ice water, or just replace both.Order AP3185407