with the injector wire disconnected can you check with a test light for current if so with ign. switch in on position ,or cranking or must the wire be connected and back probed

To test for a pulse, the injector connector can either be installed on the injector or not for the test you describe. One of the two wires is direct to ground (be sure the three sets of wires at the top rear of the engine case are positively connected), the other wire receives the pulsing signal from the ECU. The engine should be on and running.