Hmmmm. Mysterious. It certainly doesn't make sense to me since the GPS does get the signal to power off, which indicates the CANBUS is shutting the circuit off. The only thing I can think of is that I've got something wired wrong that's resulting on the CANBUS either leaving some other circuit on that's draining the battery or that the circuit isn't totally off for some reason. Was there any trick to wiring up the 12v -> 5v brick? It's been a while since I did it but I think I just plugged it in and found the positive and the ground wires and then clipped off the third one. Dave.