Originally Posted by JCL

The flicker every five seconds or so is consistent with a bad connection or bulb out (wrong resistance in the circuit) and the LCM checking the circuit at that frequency. It can often be seen when you hook up LED trailer lights, and the resistance isn't as the truck expects.

Any small draw like that can prevent the vehicle from going to sleep, and thus cause a much higher draw than the issue itself, since all the systems are still up and running.