[Decatur]

The refrigerator kept rising in temperature but the freezer was at zero. Turning down thermostat ran the unit constantly but still no cooling. Is there a defrost heater in between the freezer and the refrigerator sections? If so how is it controlled?

[woodchuck]

The evaporator coils are usually behind the back panel in the inside of the freezer so that's where the heaters will be. Heater is controlled by a defrost timer and there is also a defrost thermostat that can affect the defrost process. Here is a link on how to check the [1] timer [2] heater [3] thermostat.

Refrigerator Repair Guide: How To Fix a Refrigerator - ACME HOW TO.com