Viking Refrigerator Defrost terminator thermostat; snap-action bi-metal thermostat 058966-000, Replaces PB910259, 10442407, V10442407

Genuine Viking refrigerator defrost termination thermostat. It senses evaporator temperature and terminates the defrost heater cycle to help prevent overheating. Viking schematic documentation identifies the specification as “55 open 20 close”; related schematic notes identify an actual stamped rating of L55-35.

Is This the Right Part?

✅ Cross Reference Information

Common Symptoms

• Evaporator frost or ice buildup that progressively restricts airflow
• Freezer or refrigerator temperatures becoming warmer as frost accumulates
• Defrost heater operation not starting when the evaporator is below the thermostat’s closing temperature
• Defrost heater remaining energized too long if the thermostat fails to open as the evaporator warms

Check Before Replacing

• Disconnect electrical power before testing or accessing the component.
• Verify the thermostat is clipped securely to the evaporator and that its wiring is not visibly damaged, loose, kinked, or crushed.
• With power disconnected and the thermostat sufficiently cold, check continuity across the thermostat; the service documentation specifies that it should be closed below approximately 20°F ± 8.5°F.
• After the thermostat warms above its opening range, recheck continuity; it should open. Do not apply line voltage during this test.
• If the thermostat tests normally, inspect the defrost heater, wiring, and control circuit rather than concluding that this part is defective.

Pro Tip

Part Details

Key Features

• Genuine Viking defrost termination thermostat
• Snap-action bi-metal construction
• Normally open operation
• Documented switching specification of 55°F open and 20°F close; related Viking documentation identifies an L55-35 stamped rating
• Evaporator-mounted sensing component used in the refrigerator defrost circuit

Installation Notes

• Disconnect electrical power before servicing.
• Access requires removal of the evaporator-area cover or related freezer interior components, depending on the refrigerator model.
• Remove the existing thermostat from its evaporator clip and disconnect its wiring only after power is off.
• Install the replacement in the original evaporator mounting position and route the leads without kinking, crushing, or contacting the heater.
• Reconnect wiring as originally configured and reinstall removed covers before restoring power.

Verified Compatible Models

DDSB5423SS, DDSB5483SS, DFBB5423SS, DFBB5483SS, FDBB5361, FDFB5483SS, FDRB5483SS, RDDSB5421DSS, SAVCFB5363R, SAVCSB5423SS01, SAVCSB5483SS, VCBB363LSS, VCBB363RSS, VCBB5361L, VCBB5363ELSS, VCBB5363ELWH, VCBB5363ERSS, VCBB5363ERWH, VCFB363LSS, VCFB363RSS, VCFB5363ELSS, VCFB5363ERSS, VCRB363LSS, VCRB363RSS, VCRB5363ELSS, VCRB5363ERSS, VCRB5363RSS03, VCSB548D, VCSB5421D, VCSB5482SS

Fitment reminder: Match the complete appliance model number, including suffix or revision where applicable, before ordering.