Warm fridge, and evaporator fan not working

We have an old Amana BRF520TW which we really need to repair as it’s built into a custom made niche and the dimensions are non-standard now.

The fridge is warm and the fan behind the rear panel in the freezer (the evaporator fan?) is not working. After reading other threads here I suspect it’s a faulty defrost thermostat - there appear to be two (in series from what I can tell on the wiring diagram). I have opened up the evaporator section and I can see that one of the thermostats (the upper one in the photo) looks deformed (the plastic cap is pushed out) so it’s the main suspect at the moment.

Now I want to test the thermostat but I can’t figure out how to separate the AMP plug and socket that are used to connect them to the wiring harness. :o There’s no external clip or anything obvious to me which enables them to separate. Is there some kind of trick here?

Thanks.

I was finally able to separate the connectors using two pairs of pliars. They were impossible to separate by hand. Now off to find the multimeter…

Well it looks like both thermostats are open circuit when cold. I put the in some ice water to test - is that cold enough?

I am very surprised that both thermostats are shot.

They have different part numbers (the cable connectors are male on one and female on the other)…

12028301

10789104

Is it possible to test the evaporator fan without removing it?

How likely is it that both defrost thermostats are faulty?