I hate to say it, but if you had the kind of voltage and current spikes that would take out your headlights, the solid state circuitry in that warning module most likely didn't stand a chance.

It looked to me though like a few different combinations of inputs could tell you whether the module was operational, and that having an input on each like you listed in your first post wouldn't be necessary. It looks like one combination you could try would be to apply Power (+12 Volts) to terminal (6), Ground to terminal (2), and Ground to terminal (1). If that doesn't work (simulating that your driver's door is open), the circuit is most likely shot.