Using a voltmeter for that test is a waste of time. it's going to show battery terminal voltage regardless of whether current is flowing or not. Try using the "milliamp" scale on a digital multimeter, or an ice pick style test light. If the light glows, or the parasitic drain is over about 75 milliamps or so, you've got a leak to ground somewhere. Neither one will have anything whatsoever to do with the circuit breaker on the light switch cycling on and off.
Jerry
