How can you check a 120 volt coil?

To check a 120-volt coil, use a multimeter set to the resistance (ohms) mode. Disconnect the coil from any power source, then measure the resistance across the coil terminals; a typical reading should be within the manufacturer's specified range. If the reading is infinite (open circuit) or significantly lower than expected, the coil may be faulty. For live testing, you can measure the voltage across the coil terminals while it’s powered on, ensuring it reads around 120 volts.