Matt: Here is what I would suggest. You know it's a ground problem, probably, and it is possibly caused by a loose or disconnected ground, somewhere else.
I would suggest getting a low resistance resistor, like 1 ohm or so. Temporarily jumper the resistor across the trace which got fried, as the defacto fuse. You should be able to then turn on the car and measure a voltage across the fuse with a DVM. Once you establish what the amount is, start disconnecting source's, like headlight's, by turning them off. If the voltage across the resistor drop's substantially, at any point, then the item you removed or turned off is where you probably need to be looking for a wire which is either not connected to ground, or is loose and not making a good connection.
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