Heater failed

Troubleshooting was the most complicated. Once I had assured myself that the defrost timer and thermostat were operating correctly, I defrosted the fridge and removed the heater to find that one of the two heaters had failed. I manually defrosted the fridge until the parts arrived and replacement was easy because the wires, brackets and connector were identical to the original. the multimeter wasn't really necessary. Most of the time required was for defrosting.