[header] How to check capacitors using an ohmmeter [title] Disconnect the power source of the capacitor. [step] You should also make sure that the device which the capacitor powers is unplugged before your continue. If the appliance is instead hard wired, simply turn the circuit breaker off. 
[title] Use masking tape to label the wires that connect to your capacitor. [step] In some cases you will see terminal labels that have been printed on the housing or lid of the capacitor.