Since it's in my truck I have it connected to a phone charger that plugs into the 12v socket. It actually has 2 usb slots in it. One at 1 amp and the other at 2 amps. The 1 amp usb slot is powering the arduino and the 2 amp powers the relay module separately. I have tried many different digital pins and I have inspected the board very closely and found no breaks in the pcb tracks and nothing out of the ordinary. It looks perfect. I've just never seen a relay act like that.