I saw the thermostat on the parts drawing #5. Please recommend the best way to access this part. Thanks.

I have opened the back panel of the freezer and now more questions. I have attached a photo of what I see with the back off. First there are 2 thermostats on the coils, one at the left edge of the top coil before the fins begin. This one seems wired to the heater. The other thermostat is mounted on the top coil in the middle of the coil. Which thermostat should I replace or do I need to replace both of them? From your earlier answer I ordered one thermostat and not two.

Another question is on the wiring. 3 of the four wires on the thermostats (remember one wire goes to the defrost heater) go into the rear section of the back wall and are not accessible nor do I know what they connect to. The wire colors are not the same as the replacement thermostat. The existing thermostats have orange and yellow wires and the replacement thermostat has orange and pink. Should I connect orange to orange and pink to yellow? All wires for both thermostats would have to be cut near the freezing coils and I am worried about non sealed splices subjected to a continual freeze thaw cycles created by the defrost cycles. Is it OK to splice the wires in this area? Is there any special technique for splicing to prevent corrosion or shorting problems with the splices?

Based on these questions I did not do anything and reassembled the freezer and await your response.

Other than the defrost cycle the refrigerator/freezer is working fine so I don't think there is a problem with the compressor. Where can I get a wiring skematic for the refrigerator to help diagnose the problem?