Some short background info... My Frigidaire Gallery refrigerator/freezer (model FGHB2866PFEA) is having issues. It makes loud clunking sounds periodically and the freezer (set to 0 degrees F) gets a ton of condensation inside. I put a thermometer in the freezer that displays the highest and lowest readings. When I check it it's usually close to 0 degrees but the high is somewhere between 30-40 degrees.

The condenser coils weren't too dirty but I cleaned them anyway. The evaporator fan motor runs and the defrost heater has continuity. There was no frost buildup on the evaporator coils though. I tested the defrost thermostat and it showed continuity at room temperature which made me think it was bad. I ordered a new one (https://www.appliancepartspros.com/frigidaire-thermostat-5304521781-ap6893121.html) and when it arrived it also showed continuity at room temperature. I tried the "put it in water and slowly warm up" technique to see when it would open with no luck; I stopped at 91 degrees.

I wanted to verify the thermostat worked as expected before opening the freezer up again but at this point I'm wondering if I'm doing something wrong since the new one is behaving like the old one did.

If anyone has any advice I'd appreciate it, I'm close to tapping out and calling a pro. Thanks in advance.

Thanks for the reply. The writing on the thermostat is a little different from what I've seen given as examples:

FR-5 57/43

I'm assuming it's supposed to open at 57 degrees F and close at 14 (57-43)? the fact that both the old and new one stay closed at room temperature makes me think there's something wrong with my assumptions. I can check with someone on the customer service side at AppliancePartsPros to see if I got sent a bad one.

I left the heating element alone aside from checking for continuity with a multimeter. I saw some DIYers short the thermostat to test the heater but since there's no ice buildup and it passed the continuity check I thought it wasn't worth the risk.

For the clunking it's hard to pin down because it's random and I'm often not near the fridge when it happens. The condenser fan does come on and I don't hear any buzzing or clicking from the compressor when it starts.

I was surprised to see no ice on the evaporator coils based on all the lists of most common freezer problems. I'm probably out of my depth on this one but it was worth a try.