Engine Light Goes Off When Headlights Turned On

I have a 2000 Ford Taurus with the Overhead Cam Duratec Engine. The vehicle runs fine and when tested with an OBD II reader there is no engine codes stored in the computer. The engine light goes off when I turn on the headlights. I suspect it must be a short somewhere in the electrical system. However, I am a fairly decent week end mechanic with basic knowledge of how electricity works. However, I don't know how to go about finding the a short of this type. Any ideas would be appreciated.

When you say, "The engine light goes off" do you actually mean "turns on?" If so, I'd suspect that you have a ground issue somewhere for the instrument cluster and the cluster is completing ground through the bulb for the check engine light.

-Rod