Stumped on fixing a refrigerator - Freezer gets cold but not fridge side. fixit

Hi /r/fixit, I'm trying to fix a GE GSH25JSTASS refrigerator. (AppliancePartsPros page)

As I mentioned, the fridge part of the side-by-side wasn't getting very cold at all. There wasn't any air coming through the vent. I saw frost at the back lower part of the freezer suggesting something in the defrost cycle wasn't working. Unfortunately I took it apart after a couple of days so any buildup there would have already been melted, so I didn't witness it on the inside.

I checked the defrost limiter thermostat and it stayed closed until I put it in hot water at which point the circuit broke. That seemed to work. I initially assumed this was the problem so I actually have a new part. It seems to behave the same way when cold/hot as the old one.

Next I tested the defrost heater for continuity. Sure enough, the circuit completes. It does look very corroded though.

Does anyone know what I should try next? I could gamble on buying a new defrost heater assembly. It'd be about $40 if I wait for it to ship or $62 if I buy it locally.

Thanks very much in advance.

Submitted January 17, 2015 at 12:56PM by bubbaholy http://ift.tt/1CiEB6h fixit