When you are testing a lighting circuit for continuity (a complete circuit), any non-infinite reading on the meter is accepted as good. A cold lamp will have a relatively low resistance, so the meter should read something. It should be something close to zero, but the chances are pretty good that the reading won’t be exactly zero (zero means “short-circuit”). An open circuit will read infinite; some Ohmmeters will blink, some display “OL,” many display a cryptic “1 .”. The trouble that some techs have is twofold: If your meter is auto-ranging and you are touching the test leads you’ll get a reading, which you may interpret as a good…oops. You just checked your own resistance (the resistance of your own body, that is) and misread the results. Setting the Ohmmeter range too high can lead to the same silly results. Don’t touch the meter leads and you’ll be fine.
– From John Kaluta’s Technopolis column in the upcoming May PLSN.
