SM-S-105DM Relay Contact Wear and Welding

To confirm if the relay contacts have suffered from wear or welding, disconnect all power from the circuit. Use a multimeter set to resistance (Ohms) mode to measure across the relay's output load pins. If the multimeter displays 0 Ohms (continuity) while the relay is in the 'OFF' state, the internal contacts are physically fused together, preventing the device from switching states.

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