For now, I've modded the board for DC.
I'm fairly sure that there's a short somewhere on the board. However, nothing is smoking.
I start tracing voltage from the harness. At the pin, 5.08VDC. At the diodes, also 5VDC. But, just about every other part I can meter and get 1.7VDC, at the positive pin.
I took advice from Adam from One Circuit, and Ohm'd out every part, between ground and VDC. Every part would start low, and start climing, until I got ~80 Ohms. I was waiting to see one part give me a short, but unless I missed a component (which is possible) I'm not finding the short.
Any other tips to find this drain?