Thanks very much for this. Getting battery voltage on both b+ wires. But 6.3 on the enable signal wire when ignition turned on. Do you have any more detail on what might cause the low power and how to fix it. We have swapped in a known good head unit too and no change. It looks like power is getting to the amp but there is no measurable output from the amp. We have already replaced the amp once as well with no change. Going to try a third amp when it arrives.