Refrigerator displays E06 and may not defrost, causing frost buildup and poor cooling.

Safety first: Disconnect power. The defrost heater operates at line voltage and can be hazardous.

Steps to check:

• Access the evaporator and heater: Remove the interior rear panel in the freezer to expose the evaporator coil and heater assembly.
• Inspect the heater: Look for breaks or burn marks on the heater element (often a metal or glass-encased rod beneath the evaporator).
• Test continuity: Disconnect the heater leads and measure resistance with a multimeter. An open circuit indicates a failed heater that must be replaced with a Thermador-compatible defrost heater.
• Check defrost thermostat: Locate the defrost thermostat/thermal fuse clipped to the evaporator. Test for continuity when the thermostat is cold (covered in frost or cooled with ice). Replace if open when cold.

Note: If heater and thermostat test good, the main control board may not be energizing the heater. This requires advanced diagnostics and is best handled by a technician.