The place you hooked up the electric choke is standard. There is no power to the coil without the ignition switch turned to the 'ON' position so there's no chance of it being live the whole time (unless someone did something really stupid to the ignition circuit, which would then lead to the ICM in the distributor burning out very quickly). There must be a live continuous power issue somewhere else which has just taken place since you fixed the headlights. Did you hook up power from the battery for the new headlight harness?