Hook your test light to ground instead of 12v and do your probing with it hooked up that way. If you have it connected to 12v, it will only light when you touch a lower voltage(like ground). If you touch 12v with it it will not light. You have to have a difference in voltage across it to make it light. This is probably why you only see it when your igition switch is off. Are you getting spark anywhere? Pull the high voltage coil wire our of the distributor and hold it close to a good ground(engine block) while you crank the engine with a remote starter switch or have someone run the ignition switch for you. See if you get any spark there. If you have it there, plug that wire back into the distributor and pull a plug wire off at the plug and try the same with it.
