Condensation or moisture on exterior door surfaces or around mullion between doors.

Safety first: Unplug the refrigerator before accessing any heater wiring.

Steps:

• Check humidity: Use a dehumidifier or air conditioning if room humidity is very high.
• Heater switch: Some Viking models have an energy saver switch that turns mullion heaters off. Turn condensation control ON if available.
• Inspect gaskets: Ensure door gaskets seal properly to minimize cold air leakage.
• Heater test: If accessible, test the mullion heater strip for continuity and voltage when active.

Corrective action: Replace a failed mullion heater strip if condensation is persistent and other factors are controlled. Ensure gaskets are in good condition.