If I'm thinking right...with the positive cable disconnected from the battery the test light should be between the positive cable and the positive post, everything should be de-energized...the light should not come on, if it does disconnect one wire at a time until it goes out, when the light goes out that would indicate your power drain/shorted circuit.
Are you talking about disconnecting one wire at a time along the wire harness? Here is where I am. The engine side harness is not connected to the firewall bulkhead at all, yet I am getting light when probing the ballast resistor, the horns and the alternator wire. I disconnected them from the actual devices to so the power is through the wires.
I also probed the bulkhead for kicks and giggles and have SEVERAL that light up.
EDIT and UPDATE: Started checking wires from the furthest away from the firewall and started probing. Horn wires lit up, alternator wires lit up, etc.
Long story short. One little wire from my tachometer had burned through and was exposed against the intake manifold. this is connected to the coil which was lighting up. Short story: Tachometer is now gone. I have been meaning to do that for a while anyway.
However, a wire to the distributor still lights up. See picture. The female end that connects to the ignition control box on the firewall.
