door openings
When a kid my folks Westy unit looked about like this. Somewhere in my stuff I have the operators manual, my mom saved everything. I think it had receipes in it.. We the sold the frig with a house back about 1968, it was "the old unit" that was in the basement bar/TV area in Midwest home.
Ours DID have a counter that somehow "counted" the door openings. At first I thought this was total BS, thus I purposely would click the switch to prove that is how it worked. When the unit was older it did not defrost, either the integrator that counted clicks failed, or the heater element.
Even when the newer refridges we got, my mom still thought that they counted the door openings. ie limit the number of times the door is opened