Do you mean the GEN light?
It sounds like you might not be getting a spark?
I’m not sure it be the coil. There are a number of things you can check to get to the bottom of it. Spark plugs, condensor, contacts, HT leads, distributor cap and rotor arm.
It’s happened on a number of my cars and usually, for me at least, turns out to be a worn distributor cap and/or rotor arm. Also worth checking the HT leads are on tight as well before you start checking the other things.
