Maytag Refrigerator MTB2156FEB Freezer not defrosting

This defrost timer controls the automatic defrost cycle in select refrigerators and freezers, switching between cooling and defrost to clear frost on the evaporator. It helps maintain stable temperatures and prevents heavy ice buildup and long run times. What it does:

• Alternates the system between cooling and defrost on a timed schedule
• Sends power to the defrost heater during defrost, then returns power to the compressor and fans
• Failure can cause heavy frost on the evaporator/back freezer wall
• May lead to warmer temperatures, constant running, short cycling, or no-cool if stuck in defrost

• 1 defrost timer

• Disconnect power before servicing
• Access location varies by model
• Note wire positions and transfer them one at a time to the new timer
• Mount securely in the same orientation as the original and verify normal cycling after power is restored

This radiant-style defrost heater melts frost from the evaporator during automatic defrost cycles. Replacing a failed heater restores airflow and helps maintain consistent temperatures while preventing ice buildup on the freezer back wall.

• Heats the evaporator coil to clear frost/ice during the defrost cycle
• Promotes proper airflow for stable cooling performance
• Common fix for heavy frost on the back freezer panel, warming in the fresh food section, or a noisy evaporator fan contacting ice
• If the element tests open (no continuity), the unit will not defrost

• Disconnect power before servicing; allow built-up ice to melt for safe access
• Access from the freezer by removing the rear panel; handle the glass-sheathed element carefully
• Note wire routing and transfer any reusable shields, clips, or insulation from the original part if present
• After replacement, verify the defrost thermostat/sensor and control initiate a defrost cycle

This defrost thermostat is the temperature limit switch for the evaporator. It lets the defrost heater run when coils are icy and opens as they warm to end the cycle, helping stop frost buildup and restore steady cooling.

• Monitors evaporator temperature; closed when cold to allow the defrost heater to energize
• Opens as the coil warms to terminate defrost and protect components from overheating
• Failure may cause heavy frost on the back wall/evaporator and weak airflow or a warm refrigerator section
• Can also lead to long run times or cooling that returns only briefly after a manual defrost

• Unplug the refrigerator or disconnect power before servicing
• Located behind the freezer's rear panel on the evaporator; remove shelves/ice bin and panel to access
• Reinstall in the same position/clip for firm contact with the coil or tubing
• Make secure, insulated wire connections and route wiring away from sharp edges and moving parts