Check Engine Light (Mil) not working (LS3)

[vstol]

I put a LS3 into my 71 Corvette with a GM ECM. The check engine light does not come on when I turn the key. I have the mil wire from the ECM to the light and a ground coming from the light. I read somewhere while I was trouble shooting that the ECM has the ground so do I remove the ground from the light? Thanks
Kevin